Water Changes

Bubba12 · Dec 4, 2015

I have a 90 gallon reef with mostly LPS and softies! the tank is still new (about 3months). I am currently doing 10 gallon WC's weekly on the advice of the LFS. Not dosing anything. Everything seems to be healthy. I did a WC a week ago today and my parameters are as follows:

pH 8.2
Ammonia 0
Nitrite 0
Nitrate 5
Phosphate 0
dKH 9
Calcium 440
SG 1.025

Based on these, should I continue with weekly WC or can it be pushed backed to biweekly?

Downbeach · Dec 4, 2015

You could try to do 5 gal. a week and keep an eye on your system.

tanklife3 · Dec 4, 2015

imo biweekly would be fine

LiveWire · Dec 4, 2015

I follow the rule of 10% biweekly or 20% once a month. If I were doing weekly's I would cut it down to 5% or just 5 gallon which would give me a total of 22.22.... As long as you are getting 20% changed a month you can really do it what ever way is best for you.

maroun.c · Dec 4, 2015

You can try 10% biweekly for few weeks and check how your Nitrates and Phosphates test and decide accordingly.

Bubba12 · Dec 4, 2015

If my nitrates are at 5 after a week is it safe to assume that they would be at 10 by week two. Is this too high?

Randy Holmes-Farley · Dec 4, 2015

Bubba12 said:
If my nitrates are at 5 after a week is it safe to assume that they would be at 10 by week two. Is this too high?

Nitrate may not rise linearly. It might not always rise at all once it reaches an equilibrium where export matches import, but that may be too high once it gets there.

Water changes are not usually the best way to deal with nitrate, except the blast that comes after cycling/curing live rock.

This has more:

Nitrate in the Reef Aquarium - REEFEDITION
https://www.reef2reef.com/blog/nitrate-in-the-reef-aquarium

and this article has a ton of graphs of how different types of water changes might impact nitrate:

Water Changes in Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-10/rhf/index.php

tanklife3 · Dec 4, 2015

Randy Holmes-Farley said:
Nitrate may not rise linearly. It might not always rise at all once it reaches an equilibrium where export matches import, but that may be too high once it gets there.

Water changes are not usually the best way to deal with nitrate, except the blast that comes after cycling/curing live rock.

This has more:

Nitrate in the Reef Aquarium - REEFEDITION
https://www.reef2reef.com/blog/nitrate-in-the-reef-aquarium

and this article has a ton of graphs of how different types of water changes might impact nitrate:

Water Changes in Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com
http://reefkeeping.com/issues/2005-10/rhf/index.php

Exactly, for my tank my nitrates never get above 6-8 even if I haven't done a water change in months