How often water changes and % for a 125 gal?

[Arturosito]

Hello. I want to go bigger. I currently have a hi-tek 25 gal 60p that I've finally managed to achieve balance. It's algae-free and very nice.
I perform 30-40% WWC, and I want to go big, way bigger, 125 gal. And I just want to know what do you recommend in terms of WWC for such tank. I'm just worried about changing too much water weekly, because it's RO, and the residual water is a lot of waste for the environment. For a 25gal it's OK, but for a 125gal... yet I want to be able to keep it sparkling clean and healthy.
Picture of my current 60 p attached.

 

[hypnogogia]

You’d be looking at 50% WWC.

 

[Arturosito]

You’d be looking at 50% WWC.

Wow. Even more? Why so?

 

[ElleDee]

Just how bad is your tap water? If you can't do at least, say, 40% a week with RO you might look at mixing it with tap or just resolving to work with your tap water entirely even if it limits your plant selection. There are tanks that get by with smaller or less frequent WC, but that will probably require a much different approach entirely and greater concessions, i.e. a lower energy tank.

 

[Arturosito]

My tap water is 7.8 ph and 200 TDS

Just how bad is your tap water? If you can't do at least, say, 40% a week with RO you might look at mixing it with tap or just resolving to work with your tap water entirely even if it limits your plant selection. There are tanks that get by with smaller or less frequent WC, but that will probably require a much different approach entirely and greater concessions, i.e. a lower energy tank.

 

[hypnogogia]

Wow. Even more? Why so?

Because you’re running a high energy tank: high light, CO2 and EI fertiliser.

If your tap is 200 TDS, what is the water in your tank after water change? Also, what GH amd KH is your tap water?

 

[Arturosito]

I use RO, so the TDS is like 3 after the RO, and PH is 6.8, I haven't measured GH and KH. I use lean dosing.

 

[hypnogogia]

You use pure RO and don’t remineralise at all? If not, you could, as @ElleDee has already said, mix RO and tap.

 

[foxfish]

You could collect rain water?

 

[Arturosito]

You use pure RO and don’t remineralise at all? If not, you could, as @ElleDee has already said, mix RO and tap.

Yes, I remineralize with seachem Equilibrium.

 

[Arturosito]

You could collect rain water?

That's an idea for when I build my house. Currently living in an apartment.

 

[Arturosito]

Well the 125 gal would have sump filtration. What kind of media would get rid of the algae-feeding elements if using tap?

 

[richardcunliffe]

Are you committed to high tech? Personally, at that scale I couldn't bare regular water changes and would go for something that didn't need them. Certainly doesn't mean you can't have a beautiful tank. Plenty of people here that do do WCs at that scale though, just challenging any underlying assumptions in case that is helpful

 

[hypnogogia]

algae-feeding elements if using tap?

What algae feeding elements? Lots of people on this forum use rock hard tap water for high tech and have amazing scapes. If you remineralise with Equilibrium, then you could skip that and use tap water to remineralise your RO.

 

[Heelllooo]

Hi,

You should not go for a setup where you try to minimise WC. Lowtech or hightech.

Although you could have a stable tank with only a small WWC, it will not always be the case. Your fish get sick => do lots of WC / you have an algae issue => do lots of WC / most issue you could have => do lots of WC. You see the picture.

WC are your best friend and you should create a setup which make it easy for you to do them.

It's only my opinion but you can never do to much WC ( if you do them correctly ). Plant and fish love new clean water and you should provide them with it.

So doubling down on either using your tap, a mix tap/RO or making it easier for yourself to filter and store RO.