Emperor 280 clogging with green gunk

I have two tanks, a 65g and a 29g (nominal). The 65g has been running for 4 months, the 29g for just over 1 month. I have an Emperor 280 in the 65g and a Penguin in the 29g.

Both are on DIY CO2 (cannot afford a tank -- yet) -- 7 2L bottles (5 and 2).
The pH difference on the 65g is 6.7 to 7.8 -- but using API tests and that means two different test bottles for the 6.7 and the 7.8.

The problem -- my 29g plants are growing like crazy, and the 29g filter media has never been changed and still looks pretty good. The 65g plants are not growing nearly as well. The tank looks pretty good, some mild BBA mostly on older leaves. The main thing is that the filter media in the Emperor 280 clogs in a week and has to be changed. Its clogged with green slime. Not just once but every week for the last 4 or 5.

I know that the standard answer is "more CO2". I guess I could add a 6'th 2L bottle, but I suspect it would just be overdriving my diffusers. I have a hagen ladder overflowing into an inverted plastic tub with a powerhead blowing water across the CO2 in the tub on 3 of the bottles, and a limewood stone with a powerhead blowing the bubble stream across the tank.

I will go to a tank when I can afford to, but its the clogging filter that bothers me.

*** forgot ***
Am using EI on both -- based on the EI-Light amounts. The lighting on the 65g is 4 40w 6500's (all new). By my test kit my parameters are
pH 6.7
kH 8
gH 10
NO3 20
Nitrite 0
Ammonia 0

 

Re: Emperor 280 clogging with green gunk

Its not nice to reply to your own post -- however, this morning I put a piece of J-cloth in the media holder on the 280 and put that in front of the normal media. Doesn't solve the problem of why, but might keep from using up my Emperor media so fast.