foam and bubles

Question

Hello,
I have a 200G fresh water tank with 40G Sump.  All discus fish that I feed with frozen blood worms from a Hikari.  I've had the tank for 1.5 years now and change 40% of the water every to weeks.  I place 1 Tbs of salt per 5 gallons and only add water conditioner.  Now for the problem.  Recently when the water flows below to the sump there is a lot of foam/bubble build-up in the sump and it overflows.  I've never had this issue before and have not changes brands of salt or conditioner.  If I change out 80% of the water it goes away but after about 1 week it foams up again.  What's causing this?  What can I do?  I'm thinking a protein skimmer might help but I don't know.
thanks
-john

Answer
Hi John;

From what I've read a protein skimmer can't work in fresh water. I have never actually tried it though, just in saltwater. You might want to vacuum the gravel when you change water every time to reduce the dissolved organic wastes. If you are already doing vacuuming at water changes, do them weekly and see if it helps. It would be good to do a test of your nitrate level. If it is below 20 ppm it's fine. Anything over that will tell you that there is too much organic waste in the system. Test the nitrite and ammonia too while you're at it. If either of those are elevated at all there will be foam too.

You didn't mention how many discus you have in there or how big they are. Could it be overcrowded? If they have grown they will be making more mess than they were when you first got them too. Just a few things to consider I guess. Let me know what you think and we can go from there...

At Your Service;
Chris Robbins