FOWLR water change frequency?

[dandelion]

Just wondering how often everybody here does their water change on a FOWLR. Here's my set up:

 

29 Gallon

22 pound live rock

10 pound aragonite live sand

Remora pro skimmer

Hang on back fuge with 50gph flow

C4 hang on back filter running filter floss, 100 micron and 50 micron polishing pad, purigen and phosguard, and ceramic nodes

Instant ocean salt mix with RO/DI water

 

2 ocellaris clowns

1 firefish

1 peppermint shrimp

~6 Astraea snails

 

I have been doing 10% WC every 2-3 weeks. My tank is at six months and am currently having a controlled Cyano bloom. I suspect that and the fresh phosguard helps me attain 0 nitrates and phosphates. Now if it's just a FOWLR, do I really have to do water change as long as my nitrates and phosphates are 0? I suppose coralline algae does take out calcium and fish do need some trace minerals from the water, but I suppose WC on a FOWLR is mostly for nutrient export, which my overpowered skimmer and fuge and chemical filtration is taking care of?

[Elizabeth94]

Not sure how different FOWLR's are in terms of nutrients, but when I had my 29gal mixed reef with 2 clowns and a royal gramma, I only did 5gal water changes every 10days or so. Everything was doing great for two years on this schedule until I got a frag with bryopsis on it.

 

Your stocking is good but I think you might benefit from smaller weekly water changes instead of one big one. As far as changing water when you have little to no readings, yes I would still do water changes. If you have cyano you have an excess of nutrients, your phosphate test may not be accurate, or the algea is consuming it before it can register.

[dandelion]

I do intend to add another royal gramma but then I had ick in my QT so it was torn down let dry and I've only just gotten it back up and running. So maybe in another 1-2 months I'll finally be able to add a royal gramma.

 

I'm pretty positive the phosphate was removed by my Phosguard. Last night I tested my water it was about 0.5 and then I replaced the phosguard. Today morning it was 0. I do think the cyano is chewing up my nitrates though coz it's usually around 5-10.

 

Was hoping to get an excuse to be lazy and skip a water change.