A couple newbie questions

[bearrock]

I have read most the stickies and have they have been able to answer the majority of any questions that I have had. One however still remains unclear.

I have a 29gal tank with a sump filtration set up. My pump is rated at 785gph. This gives me a turn over rate of ~ 27 times an hour. From the overflow the water passes through filter floss then a 100um sock. I have a 50um and a 1um sock for further polishing after the tank has finished the cycle process.

How many fish can realistically be kept in the tank while keeping my water changes to no more than 2 times a week? I understand that the size of the fish matters so lets approximate 2-3" fish.

I also have a slightly larger pump that would increase the turnover rate to 33 times and hour but would require changing all return tubing. I have a 90gal tank that I would like to save the larger pump for.

I apologize if I missed the thread that would spell this out for me.

 

[Oughtsix]

There is simply no hard and fast rule. With a sump I am guessing you will have plenty of bio filtration. You can build the bacterial colony up by slowly adding fish. The bacteria should keep up with breaking waste down to Nitrates. Twice a week water changes should do an excellent job of flushing the nitrates out of the tank. If your sump is setup in a wet/dry configuration (i.e. bio balls in the air with water trickling over them) you should have plenty of O2 in your water (put a couple air stones under your bio balls if you haven't already). It sounds like you are setup to handle a large load of fish.

The more fish you have the quicker the tank will spiral out of control if/when something does go wrong. The longer your tank is running and the more comfortable you are with its stability the more fish I would feel comfortable adding. A slightly higher volume pump isn't going to make a huge difference in how much fish load your tank can handle.

Cleaning your mechanical filtration media when you do your twice weekly water changes will greatly improve your water quality by removing the waste BEFORE it breaks down to Nitrates.

 

[Ogre One]

Just saying this but the faster that pump works the less time the ammonia has contact with the BB. But do as u please.

 

[bearrock]

Correct me if I am wrong but the speed of the pump would have nothing to do with shortening the amount of time the water is in contact with the BB. In theory the larger the pump the more times any one area of the tank will pass over the BB but from the over flow to the drip tray and to the bottom is all gravity fed. So by increasing the size of the pump you would actually (in theory) increase the amount of times that any given area is in contact with the BB but not in any way shorten it. In short the water passes from the drip tray over the BB at the speed of gravity regardless of the pumps GPH.

It is a wet dry system and I would say there is 4-5gal of BB in the sump. There is about 12-14" from the drip tray to the bottom. Do you think it would still be necessary to add the air stones? Cleaning the mechanical filtration twice a week would not be a problem either.