# Water change schedule



## aselvarial (Feb 21, 2014)

I have been playing with my water change scheduling lately. My fish and plants were getting stressed with weekly water changes, so I wanted to see how far I could stretch them. I went every other week at first, testing my water, and watching both my fish and my plants. Everything tested at 0 (I get no ammonia, nitrates, or nitrites in my tanks at all), plants were growing a little better, and fish seemed happier. So i went to 3 weeks. Same result. Plants looking healthier, fish happier, even my snails and shrimp seem to be doing well. I went to 4 weeks. 1 water change a month. My plants now have to be trimmed every 2 weeks, my swords are FINALLY doing fantastic, my duckweed has to be culled every 10 days, and my shrimp are finally breeding! My fish are happy, my snails look good, and my water test still show nothing. I've been doing once a month water changes for about 4 months now, and my tanks look better than ever. 

Once a month water changes appear to be making everyone in my tanks happier! I've been watching the 2.5 gallon, and the 5 gallon more closely than the 10 and 20 gallons, but even they seem to be doing well on the 1 time a month change. (caveat, everyone DOES get about 10 percent of their water topped off once a week as it evaporates pretty quickly)

Could there be something in the heavily planted tanks that make more frequent water changes a bad idea? Is there something I could be missing that might cause problems over the long run? I've now totally stopped using fertilizer in my tanks, and even the swords still seem to be doing better on this longer schedule. 

Does anyone else do long periods between water changes?


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## Mousie (Feb 16, 2015)

aselvarial said:


> Does anyone else do long periods between water changes?


Never, unless I'm on vacation.


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## mattdocs12345 (Oct 13, 2014)

What looks like you have going on is silent cycle combined with BB. Not an expert on water change schedule but with oldfishlady suggestions 10 gallon tanks can have once a month partial water change as long as plants are growing fast.


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## aselvarial (Feb 21, 2014)

My tanks are cycled. Have been for over a year. I think the stress is caused by swings. My ph in my tank is 7.6 and tap water is 6.8. Also, my water is VERY soft out of the tap, but, as I add calcium for my snails and shrimp, my tank water is much harder. I don't remember the exact numbers for tds, gh, and kh, but the differences are pretty drastic. 
It's odd though that my swords are doing better without fertiliser on the extended water schedule, than they were in the once a week with fertiliser.


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## Dalloway (Apr 13, 2014)

aselvarial said:


> It's odd though that my swords are doing better without fertiliser on the extended water schedule, than they were in the once a week with fertiliser.


If you mean you added in liquid/water column ferts then it makes sense if you think about it this way; swords are among the minority of aquatic plants in being heavy root feeders primarily. Water column fertilization is not going to do much for them and the prolonged period of time between water changes ensures that mulm and organics are going to be present in higher concentration in the substrate thus becoming more available for the roots.

I've known people that have gone months without water changes, just topping off. In a healthy and established enough (and understocked) tank it did not affect the inhabitants and nutrients replenished themselves via waste, food etc.. 

I would say though that it depends primarily on your water source. My tap tends to be bipolar so I have no experience doing the same as I mentioned above since I need to tweak it so much and hardness gets used up so quickly (my pH comes out either maxing the high range pH test or the low end of the regular pH test, it's that bad. My GH/KH come out at 4-9 dKH/GH but both drop to 2. My pH drops to 6.4 in 2 days but stabilizes at 7.2 in tank. It's quite awful ;~;.) but I've done every other month water changes in a 20 gallon before when I had a Betta that used to get stressed out and bite himself to smithereens after maintenance. So long as the hardness, pH, N compounds, and bacteria and/or plant mass are stable and happy; I would say it's ok..? While regular water changes are important to replenish the minerals/electrolytes and whatnot, if they do not become depleted over the course of the period prior to maintenance then it's really the same effect waiting one month as it is a week. 

Since your water is soft as well, I would watch carefully the hardness and pH values. I once went 5 weeks without a water change in my 10 gallon when I got ill a year or two back and that thing crashed with a vengeance. pH was acidic enough to kill my bacteria and it took 5 water changes (small and spread out to reacclimate everyone) just to get it back to regular levels. Despite adding buffers, my hardness still depletes rather quickly too. And in my opinion that's the danger of it. When it does crash it becomes a much more delicate procedure to fix everything.


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## Paigeyy (Sep 4, 2011)

It depends on how heavily stocked your tank is, but since it seems to be doing fine, your tank should be established. The bacteria will eat all the ammonia and nitrite in the tank and the plants will use up the nitrate produced by the bacteria when they're growing. 

Your plants are growing better because of the higher nitrate levels in the water because you're not removing the nitrates during your water changes. Nitrate is a compound used in many plant fertilisers. I'm not sure about aquarium specific fertilisers, but in aquaponic solutions and crop fertilisers, nitrate is pretty much always used. So essentially, you're fertilising your plants by resisting the urge to change you water 

Changing the water over and disturbing the balance your tank has established will stress your fish to some degree depending on the individual fish.

Remember to watch your pH because the bacteria will lower your pH when ridding the tank of ammonia and nitrite. Looking after barramundi I had to adjust pH daily or every other day, but water changes were only needed to remove faeces as they were unaffected by nitrate up to 600 ppm (tolerance is species specific).


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## aselvarial (Feb 21, 2014)

Thanks for the input! I've had the tanks up and running for well over a year as fully planted tanks, but I kept up with the once a week changes until about 4 months ago (tanks over a year old at that point). I have low bioloads and I know everything is way over filtered, plus the bajillion plants, so i knew it could probably handle the longer change. 
It's nice that resisting the urge to change the water has helped the plants. My fish seem happier too so I'll keep testing and stay with this schedule for now. If it looks like hardness drops, ph drops, or I get any rise in ammonia, nitrites or nitrates I'll revisit this. But since I'm planning a move and planning to rescape all the tanks then, I'll likely have to start back over again anyway with the more frequent water changes after the move. We'll see what the water is like there.


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