How often do you change your water?

[dereks]

I live in a chronic drought area now so I do less than an optimum 50%+weekly WCs...But all my tanks are at least medium or more planted with low fish stocking. I'm a rare tester, but when I do, I never see more than 5ppm nitrate at most. I know that's not the entire tank picture as Bob alluded to, there's a major "squish factor"...but some of that comes with experience...When in any doubt, change more water more often! That's my mantra & has been for almost 30 years. It works!

Forgive my reading comprehension here, you're saying 50% WCs are Ok?

I'm asking because I've always been afraid to do more than 40% since I don't really understand EXACTLY what's happening in my aquarium other than both toxins & bacteria are building and my goal is to remove the bad stuff w/o removing too much of the good stuff. Too much detail? Lol

What prompted me to post the poll was this guy, that works at the fish store, said my weekly's were too often, I kept my mouth shut but sort of disagreed with him based on my shallow understanding of it.

I get there are many variables but still thought the poll would useful as a general guideline.

 

[Rbishop]

I can't see frequent WCs as an issue in general...some exclusions would be for high maintenance planted tanks or maintaining set water conditions for breeding or wild caught fish.

 

[dougall]

In my eyes, the biggest factors in changing water frequency and amount, is that you want to keep your water parameters as steady as possible.

if you have wood leeching tannins to the water, or rock raising the hardness, it will have an effect just like the nitrates rising which is what we would typically measure.

if you water chemistry changes quickly in your aquarium due to hardscape or whatever, it's normally better to do smaller changes, more frequently to keep nitrate down, but water conditions fairly steady if the aquarium water differs from what comes from the tap.

One reason, with certain types of planted tank, would be using something like the estimative index, where the reasoning is that having enough nutrients for plants will allow them to out compete algae and thrive... the 50% WC weekly is to keep the amounts of the ferts at a maximum value.. there's math involved so you can google.. but basically you reach a point where the amount of ferts added to the tank equals the amount taken out with 50% of the water... so there's a maximum created there,

A big reason to be able to do a large water change, is if there's an emergency, say someone knocks over a pound of fish food into your aquarium, you can vacuum it out right away without worrying what the effects will be on the tanks inhabitants., if you routinely change 5 oir 10% a week, that's potentially going to be more of a shock to the fish.

 

[FreshyFresh]

None less than 50%, once per week. On my oscar and severum 75g, I dump the water until they start to flop over.

 

[tanker]

I am a believer in large WC, at lease 50% if not more. I target for weekly changes and I almost never miss unless I am sick, ect.

 

[fishorama]

I agree with dougall, if your tank & tap water are much different smaller more frequent WCs are better than larger 1s. & if your nitrate goes up over 20ppm you either need to do more frequent or larger WCs & maybe fertilize less That's just a ballpark number. If your tank is heavily stocked or you tend to over feed that might happen faster than once a week.

The best way is to test nitrate & maybe KH & GH often until you get the hang of what WC schedule works best for your tank. Assuming it's cycled & you don't add a bunch of new fish, you probably don't need to test ammonia or nitrite. You want to avoid big swings in those first 3 parameters. Some people also have seasonal changes in their tap water too, I did in MA.

It's when you don't change water much or often that can lead high nitrate & TDS (total dissolved solids) that bad stuff can happen if you suddenly decide to "make up" for missed WCs. See "old tank syndrome", "osmotic or TDS shock", & the older, wrong thinking of "pH shock". I'd do many small WCs if nitrate were 40ppm or higher, 80ppm is an emergency in my book...but daily or every other day 10% WCs is the safe way to lower it.

Fish grow faster & are healthier with lots of clean water, plants help too. When I raised small discus I fed 5-6 times a day & changed 50-80% daily. When I had a shrimp & plant tank that got fed only a couple times/week, I did smaller less frequent WCs, although for their size shrimp poop a lot, lol.

You need to take everything lfs tell you with a big grain of salt (NO, freshwater fish don't need salt, lol). There are other ways of keeping fish, I have a friend that only tops her planted tanks & her TDS is almost the same as mine. BUT there are other parameters to our tanks we can't easily or cheaply test for, nitrate & TDS are just 2, there are also hormones, disease vectors & "other critters" that can be present in "healthy" tanks.

OK, sorry to go on & on, but next to loaches, water quality is 1 of my "things"

 

[mbunabum]

Typically 50% weekly to two weeks max all tanks... On my 125, I drain 60-70% while refilling with hose to full then drain again to same level and refill.

 

[authmal]

Forgive my reading comprehension here, you're saying 50% WCs are Ok?

I'm asking because I've always been afraid to do more than 40% since I don't really understand EXACTLY what's happening in my aquarium other than both toxins & bacteria are building and my goal is to remove the bad stuff w/o removing too much of the good stuff. Too much detail? Lol

What prompted me to post the poll was this guy, that works at the fish store, said my weekly's were too often, I kept my mouth shut but sort of disagreed with him based on my shallow understanding of it.

I get there are many variables but still thought the poll would useful as a general guideline.

All that said, I've been considering reducing my water change quantities. I've been <10 on nitrates for months, now. I'm thinking about waiting until the nitrates climb up to ~20 before doing a water change. I don't know how that'll impact the health of my fish, but it would seem that it wouldn't be detrimental.

 

[Rbishop]

@ dereks.....the WC isn't going to remove BB....it will lower dissolved solids/TDS and replenish other necessary minerals. The closer your tank is to your tap water is better in general.

@ autumnal...concur, if your stocking and feedings just causing a 10 climb in a week, I don't see why you can't extend the time between WCs.