# Old tank = no water changes?



## ThatFishKid (Aug 9, 2008)

hey, this question is just out of my own curiosity.
My 29g has been running for 4 or 5 years, and I can't remember the last time i did a water change. I know they are beneficial, but my tank seems to do poorly with water changes (a.k.a. something always goes wrong, so I just stick to topping it of when it evaporates). over the years, the tank has been colonized with tiny worms, copeopods, and other critters that help control waste. The 4 inch gravel bed provides lots of room for beneficial bacteria, and i only 'replace' filter pads and media maybe every 4-6 months. I usually just rinse it thoroughly, so I am keeping my bacteria. Would the level of biological filtration and age of my tank have helped reduce the need for water changes?

(I'm serious about this. It's been at least a year since the last water change. strange?):razz::


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## justintrask (Jun 29, 2008)

I havnt changed water in my 29 or 10 for at least 4 months. They seem to be doing better now then they were when I was doing more frequent water changes


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## ThatFishKid (Aug 9, 2008)

hmmm, this is quite curious.


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## rick1574 (Oct 10, 2008)

subscribed, i want to see about this...


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## Osiris (Jan 18, 2005)

I am usually notorious for doing water changes, but i am aiming to breed fish so its necessary. My 210g, will go for a month to 1.5months between water changes. This last stretch was 7 weeks. I didnt notice difference either way but its not overstocked. If the tank is to the limit it will make a difference


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## BV77 (Jan 22, 2005)

My two cents......when water evaporates, the minerals and heavy metals remain....adding water time after time, lets these contaminates build up, eventually reaching a toxic level. Check with your local water company, all tap water has "acceptable" levels of arsenic, lead and other heavy metals in it, along with dissolved sollids, nitrates etc......I advocate regular partial water changes.


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## fishboy23 (Feb 18, 2006)

What if you use R/O BV? Just adding to the discussion...
Out of curiosity, does the 4" gravel bed include sand at any point? 
How tall is a 29? and what kind of filter? 
I have a theory brewing, but need to know some specs...


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## ThatFishKid (Aug 9, 2008)

yea, there is sand mixed in. its a mixture of pea gravel, eco-complete, and pool sand.

filters: submersible ELITE stingray 10, HOB penguin 125, and HOB (Second nature whisper 2???) 
the tank is about 22" high
Its a planted tank, so I know that helps a lot, but stilll...

also, what is R/O BV?


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## emc7 (Jul 23, 2005)

fishkid is in atlanta. We have almost nothing in our water (TDS < 70 ppm). It might as well be rainwater. If the topoff only tanks do better, it means that those fish, plants, & snails need the minerals to accumulate. So some cichlid salts or other supplements may be appropriate. IMO: The main danger (the one that will kill your fish first) of no water changes here in soft-water town is that the bottom can fall out of the pH as the "organic acid levels" (nitrates) go up. By that long list, I'm guessing the tank is heavily planted and that's keeping the nitrates in check. I'm told it is a bit risky to go for a long time without a water change because when you do change water, the incoming pH (lately 7.5-7.8 here) can shock fish living in lower pH.


RO is reverse osmosis, BV is aimed at poster BV77. I've heard of salt-water tanks getting topped off with RO, in theory it keeps the water chemistry unchanged because nothing is added. Might help in those with that heavy-metal tank water. But I think we have the opposite issue here.


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## Osiris (Jan 18, 2005)

Yea in reef tanks if setup properly can go several several months without water changes. But they have rocks that constantly filter the water and live plants to remove nitrates, and the substrate keeps releasing calcium and other things into the water. The Salt mix contains all trace elements needed. But overtime if the tank has corals, people do dose the tank with Iodine, and other minerals.


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## emc7 (Jul 23, 2005)

People in hard-water areas that are topped-off only have water that gets even harder and higher in pH. Then a large water change with lower pH water is risky for the fish. 

The conundrum is this, the longer between water changes, the greater the risk that "something will go wrong" when you finally change water. 

The "old school" way of dealing with this 30 years ago in Chicago was to top-off only for 1-2 years, then take the fish out and break the tank all the way down, rinse the gravel in the sink and start with new water. If a tank wasn't broken down periodically eventually (sometimes years later) you'd hear that a whole tank full of fish had died for "no reason" and then the tank would be cleaned.

"Old school" isn't something I recommend even though there are now nitrate-absorbing substrates you can buy. With a nitrate absorbing substrate and RO topoffs, it should be possible to manage a cichlid tank like a salt tank, but I haven't tried it. 

I think it makes more sense to do small, regular water changes and my riverine fish seem to prefer this, they perk up after a water change. I do think a total tank break down can be a way to deal with a tank that is "out of whack". If I get a tank with a dangerously low pH, I move the fish to another tank with a little of their water and fill it up SLOWLY with clean water while keeping a close eye on the fish. 

Varying water change schedules can be a way to trigger spawning. Most S. American fish live through a "dry season" of less rain, warmer temperature and low water levels, followed by a "rainy season" of more rain, high water levels, cooler temps. In non-running bodies of water, no rain = no water change. In running water, no rain=less water change. It is common to crank up the temp and then do a large water change to trigger spawning. I hadn't heard of withholding water changes but it might be worth a try for stubborn fish, esp. in a planted tank.

IME when "neglected" fish do better and start spawning, its often after that tank has gotten covered in algae. Whether they feel more secure behind green walls or if the fish just feel there is now food for fry, I don't know.


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## Georgia Peach (Sep 23, 2005)

interesting..


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## fishboy23 (Feb 18, 2006)

ThatFishKid said:


> yea, there is sand mixed in. its a mixture of pea gravel, eco-complete, and pool sand.
> 
> filters: submersible ELITE stingray 10, HOB penguin 125, and HOB (Second nature whisper 2???)
> the tank is about 22" high
> ...


Thanks emc, for clarifying the R/O BV bit...
Here goes the theory, because it could be possible...I think the tank is a little on the high side, but maybe.
There are some that use "deep-substrate filter beds" (or some variation of this) where they basically use a tank like a 20 long, pump water through it and have a massive sand/gravel bed (often 5-6 or as much as 8 inches thick) with plants sometimes that acts as a massive biological filter for a larger tank, or you can even have just that 20 long as a tank. The point is water movement over a very deep substrate allows for good water exchange thru a lot of bio-loaded substrate, something like what happens in a stream in nature. The idea is that you get a full biological filter existing in your substrate. It takes a lot of substrate to do this, and 4" is a significant amount, but not quite what is generally considered "sufficient". Either way, you will probably get this effect to some extent with even a centimeter of substrate, but it takes much more to get a significant effect. You may well be on the border of "sufficient" effect, and your substrate is your major filter. Coupled with the biological in your HOBs (and plants), and that's a LOT of filtration, allowing you to go a long time without water changes.


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## emc7 (Jul 23, 2005)

I see the big thing as the plants. Any "good enough" bio-filter will turn all the waste into nitrate. Its the nitrate buildup the usually punishes you for not changing water. Rift lake cichlids in hard water will live a long time with high nitrate, but its a risky practice with most fish in soft water. Its the plants that subtract nitate that change the equation. I would like to see the numbers (pH, kH, gH, nitrate ppm). But I'm guessing that his bioload is small enough that the plants are consuming all the waste the fish and snails put out.


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## ThatFishKid (Aug 9, 2008)

ah, ok. they don't get the ph shock, cause i keep my ph just above 6.5, and i lower the ph before I add it to the tank.
And yes, it is fairly heavily planted. not like one of the plant dedicated aquascapes, but the plants i have reproduce and grow fast, so I have a good bit. also, the solid wastes don't get the gravel all nasty like in my unplanted tanks. this is because the worms and such the I mentioned seem to break it down. I guess that helps the plants absorb it easier. because of this, I leave the gravel alone, because it is basically self cleaning (MTS and little organisms breakdown the solids, then the plants and bacteria do the rest.) stirring my gravel only produces bits of old plant matter, and not a whole lot of it, so I don't tend to even bother.


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## Mr.Buggy (Nov 6, 2006)

I know from experience that high nitrate build-up can crash the ph in the tank. My tanks have no real plants so the nitrates get high (40 ppm or a bit above) frequently. I only do water changes about twice a month, hence the high nitrates and I tend to lose fish that stay near the bottom....kribs, corys etc...because of this. I put tuffa rocks in my tanks to buffer the ph to prevent the crashes. 
I've also noticed that I have a higher death rate immediately following a water change. Could it be gases or other things getting stirred up from the sand during the water change that's causing this?


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## trashion (Aug 24, 2007)

I feel like adding tufa isn't going to help you....Why not just do more frequent WCs?


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## Buggy (Oct 17, 2006)

The above post was from me, Buggy. I didn't notice hubby was still signed in when I posted. LOL


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## Buggy (Oct 17, 2006)

I, myself, don't do the water changes in my tanks as I'm physically not able to do them by myself. Hubby does the changes and I do the vac. His work schedule both on his job and at home, doesn't afford much time for tank maintainance so he does them when he can. The tuffa has been working great for about 5 months now at keeping the ph in the neutral range. It was running below 6.0 and is now steady at 7.0. My city water supply has chemicals to soften the water and it was killing the buffering capacity so even with more frequent w/c the ph was dropping (sometimes 1.0 or more) in a 24 hr. period and I knew that wasn't good for the fish. I chose the rocks because it is a constant source that doesn't have to be continually replaced as opposed to the powders that would have to be used at every w/c or trying to replace all of the substrate with crushed coral sand.


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## emc7 (Jul 23, 2005)

> I have a higher death rate immediately following a water change.


Water changes shouldn't kill fish. You could try upping your dechlor, some water department are double dosing chlorine because of the drought. 



> Could it be gases or other things getting stirred up from the sand


Does it smell like sulfur when you change water? I haven't seen it myself, but "anerobic pockets" are supposed to occur in thick sand beds and release HS when disturbed.


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## emc7 (Jul 23, 2005)

To be honest with you, although I advocate weekly 10% water changes, I seldom manage it. I'm more likely to do 25-30% every other week. Sometimes 60% after 3 weeks, or even go a month and then move the fish and do 100%. I do watch the pH, but since I moved here to Atlanta, I have only killed 1 tank of fish with a water change and that was when i screwed up the buffer (never overdose acid buffer!). We are lucky to have a reasonably clean, consistent water supply. If your water supply is inconsistent or potentially toxic, small, more regular changes are more important because you don't dare do a large water change.


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## Buggy (Oct 17, 2006)

It does have an odor but not sure I would decribe it as sulfer. I assumed it was from the fish waste and mulm in the filters. How can I prevent gas pockets from forming in the sand bed? What is HS?


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## emc7 (Jul 23, 2005)

Tuffa should help in the same way that crushed coral or limestone in a filter bag helps. Hardness support add 'buffering capacity" to the water. Some people add baking soda for this purpose. I use limestone or crushed coral in my African tanks as well as cichlid salts and I use a low dose of SeaChem's Neutral Regulator in my softwater tanks.


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## emc7 (Jul 23, 2005)

Hydrogen sulfide, it smells like rotten eggs or sewer. Some people advocate thin sand, some use snails or fish that like to burrow, others stir the sand with am stick periodically. I don't have any way for you to tell if this is your problem or not.


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## ThatFishKid (Aug 9, 2008)

stirring the sand periodically removes these. malaysian trumpet snails or other things that burrow in the sand can help reduce them, and plants can pretty much eliminate them (If you have enough plants, that is)

also, Earlier, I wasn't really able to tell weather my tank is 'heavily' or just moderately planted, so here is the tank in question:


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## emc7 (Jul 23, 2005)

To me it looks heavily planted and lightly stocked. I don't know if the true plant geeks would agree with me. Let me ask you this: If you cut off all the plant's new growth in a week, would it weigh as much or more than all the food you put in in a week?


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## ThatFishKid (Aug 9, 2008)

at least as much or more. The watersprite grows like a weed, the giant hygro is a bit slower though. my tank is pretty well stocked though, it's just that most of the fish either camoflage, bottom dwellers, or are hidden. 
here is my stocking and such. http://www.fishforums.com/forum/general-freshwater/21488-29g-almost-way-i-want.html


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## Buggy (Oct 17, 2006)

I have a gazillion mts in that tank, sometimes the sand looks like it's alive. No rotten egg or sewer smell so I guess it's not the gases.


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## Manthalynn (Aug 23, 2008)

I LOVE the looks of this tank. This is what I'm aiming towards with my 29g.

What type of lighting do you use? And do you use CO2?


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## ThatFishKid (Aug 9, 2008)

Manthalynn said:


> I LOVE the looks of this tank. This is what I'm aiming towards with my 29g.
> 
> What type of lighting do you use? And do you use CO2?


I don't have a source of income at the moment, so alot is whatever i manage to get my hands on
I use CO2, through a DIY system. I don't know my ppm, but i use the jello mix method, and i broke down a sponge filter and stingray that had missing parts and used them for the diffuser and reactor.
as for lighting, I have 2 24" lights over it. One is stock and one is a special plant light, giving me about 50 wats, then i have a flourecent spotlight, adding another 60, so thats 110 wats. around 3 wpg. I need a better system, because this is in my bedroom....which now stays around 78-80 degrees.
Also, I use a triple dose of Flourish fert, but since this is expensive, my plan once that bottle runs out is to buy powder ferts (iron, magnesium, etc.) from the local nursery. apparently, these are MUCH cheaper and more effective in the long run.

It took me forever to get this look, but I'm finally not embarrased to show my tank. (It used to be a wreck.)


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## Manthalynn (Aug 23, 2008)

Yes, you should definitely not be embarrassed about this tank! (Then again, I am still a newbie myself...)

Thanks for the specs! Wish I could be a MacGyver as you and create things from the parts I have. Sadly, not gonna happen...

~Sam~

PS: I laugh whenever I read your comments about your being limited by your family as to how many animals you can have...that used to be me! Now that I'm on my own, the only limiting factor is time and money (and oh how that is limited!)


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## ThatFishKid (Aug 9, 2008)

yup. I'm almost there. over the summer when I move into the basement, the limit goes away!

but back on topic, I'm starting to think that the main 2 things that allow my tank to go so long is the detritivores, wich break down the solids and such, and the plants, which absorb nitrates and most of the heavy metals that are in the water. I assume that is why I also dont get mineral build up on this tank when water evaporates. 

Hopefully someone like Kristin will take a look at this eventually and put in her 2 cents on the effect the plants have.


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## Willow (Mar 20, 2005)

If I don't do enough partial water changes, my nitrates go through the roof and my fish get dropsy. Especially the goldfish, it seems. The tropical tank can go quite a while without a PWC, but if I don't do the goldfish tank at least once every 2 weeks, they get sick. And I only have 3 fancies in a 55g tank. I guess if the plants absorb the nitrates, it's not such a big deal.


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## emc7 (Jul 23, 2005)

Fish load varies quite a bit. You say 10% a week, but a planted tank with a few fish needs less than a big cichlid or goldfish tank without plants. Nitrate sneaks up and not all its effects are obvious. You sometimes hear that fish become "acclimated" to high nitrate. And although fish that are used to it do die later in high nitrate than fish that aren't used to it, they die faster than fish in clean water.


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## mrmoby (Jan 18, 2005)

This is interesting because I have been pondering this point myself. I get so much evaporaion that I do frequent top offs, especially during the summer, but i have found myself doing water changes less and less frequently. I have found that my fish seem to do much better with the less frequent changes.


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