Weekly water changes for 90gal

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Philly33

Aquarium Advice Freak
Joined
Mar 10, 2011
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How much should I change weekly? I've had people tell me 10gal some say 30-40%. Please advise and why?
 
Really depends on how heavily you are stocked, what type of filtration you have etc. Can you give us the run down on your tank?
 
I think it's heavily planted. 18 various plants low-med light. Dosing liquid carbon. G6 and Emperor 400 filtration.
 

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Small fish load now. Flying Fox, Siamensis, 6 otos, 2 bamboo shrimp and 2 dwarf hara hara cats. Getting pressurized co2 setup for Christmas. Then adding some schooling fish.
 
I never change less than 30% a week even with a low bioload... mostly because the live plants need trace minerals replaced.
 
I never change less than 30% a week even with a low bioload... mostly because the live plants need trace minerals replaced.

yeah i agree usually if u do big water changes 50%+ you will see a big change in ur plants they seem happier and you will notice new growth, also how much of a water u want to change its up to u, i usually do anywhere from 50-80% water change and the fish and plants are happy
 
That's tough with a 90gal. I'm doing 30gal 33% weekly. I have an RO/DI filter but 45gal weekly is a lot.
 
My larger tanks get a 25% change, the small tanks (less than 3 gallons) get 50 - 75% depending on how quick I can cut off the siphon.
 
Water Changes

Hello Philly...

If you're going to the trouble of hauling out your water change equipment, then IMO, you need to make it worth the effort.

I change 60 to 70 percent of the tank water every 6 to 7 days in my large, planted tanks. Trust me on this one. The more water you replace and the more often you replace it, the better.

Large, frequent water changes accomplish two things: You don't need to overfilter your tanks, because the filters are just filtering water that's already clean.

The other benefit is, you never have to test the water conditions, because by following this routine religiously, there's no time for pollutants to build up before the next large water change. By flushing a lot of pure, treated tap water through the tank, you're guaranteed the tank water is stable and this is the most important thing for your fish and plants.

B
 
Philly33 said:
That's tough with a 90gal. I'm doing 30gal 33% weekly. I have an RO/DI filter but 45gal weekly is a lot.

I agree with what has been said.
Are you adding anything back to the RO/DI water to replace the minerals/buffers? Very important.
Why aren't you using your tap water?
 
My tap water is terrible. Yes, I am buffering my RO water. I will try to increase to 45gal 50% WC. It's tough because I have my RO system in the basement and that's a lot of water to lug up stairs. I guess by summer I'll have huge calves. Lol

All of the your input makes sense. I'll give it a go. Just hope they make 45gal garbage cans. Wifey would kill me if I used multiple cans.
 
Hello Philly...

If you're going to the trouble of hauling out your water change equipment, then IMO, you need to make it worth the effort.

I change 60 to 70 percent of the tank water every 6 to 7 days in my large, planted tanks. Trust me on this one. The more water you replace and the more often you replace it, the better.

Large, frequent water changes accomplish two things: You don't need to overfilter your tanks, because the filters are just filtering water that's already clean.

The other benefit is, you never have to test the water conditions, because by following this routine religiously, there's no time for pollutants to build up before the next large water change. By flushing a lot of pure, treated tap water through the tank, you're guaranteed the tank water is stable and this is the most important thing for your fish and plants.

B

i totally agree i used to test every 3 days but since i do 50-80% weekly i only test when something seems different

My tap water is terrible. Yes, I am buffering my RO water. I will try to increase to 45gal 50% WC. It's tough because I have my RO system in the basement and that's a lot of water to lug up stairs. I guess by summer I'll have huge calves. Lol

All of the your input makes sense. I'll give it a go. Just hope they make 45gal garbage cans. Wifey would kill me if I used multiple cans.
also what you could do is mix the ro/di water with the tap to make it safer
 
Nobody can tell you how much to change. Your testing will determine that. Once you test the same thing over and over, and you become lazy, you can generally get away with doing the normal routine... however, that can also lead to problems.

If you're dosing ferts, some methods require 50% water changes, some require smaller, etc.

It really all boils down to what works for you. What works for me and what works for you isn't going to be the same.
 
My water is a partial mix of city water but still requires a softener.

Thanks Everyone!

Happy Holidays!

I'm sure it's not my last post before New Years. Lol
 
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