Cycling With Fish...Stagnation

[lance]

This is more so in a reef tank. In a FO tank its not so important. Im not sure if this will be a reef tank anymore.
A 40% change would be done for extreme problems. Changing to much to often could throw PH and other elements to either rise to high or go out of wack. Then your removing water thats more mature. This could cause your bacteria level to drop as older and younger bacteria would be affected. Then theres the temp. differance if not done right.
Your beneficial bacteria is all over the rock and sand and like other stock they like steady readings. Extreme changes isnt good for the older and younger ones and could leave them lower then your load which could mean other problems.

With all that said i think the ammonia source would be from 2 or 3 sources and water changes alone wont fix.

Your LR and LS will convert ammonia into harmless nitrogen but not if flow is to low or to high or if poor feeding habits are in place.
Then water source like tap takes time to build levels like nitrate and phosphate and ammonia and whene it reaches readable levels its harder to control and tap isnt constant as 1 water change could add unwanted levels.

[jcarlilesiu]

I disagree with these last few posts.

I understand where lance is coming from in regards to a sw tank, but the op was discussing an fw tank with ciclids.

Continue to do large water changes as necessary to remove ammonia and nitrites and keep at a safe level for your current inhabitants. Large water changes may extend the life of your cycle slightly, however; your current fish and snails will be appreciative.