Join Date: Nov 2008
Location: Fort Collins, CO
Is the filter sleeve just the big blue thing? I'm not familiar with the Magnum canisters, but looking at it online it seems like it's just a big sponge. Is that right? If so, I doubt you have much biological filtration going on. Is it, perhaps, possible to get some sort of bio media in it? And with the Magnum rated at 350gph, the other two are probably totally obsolete and doing more harm (off-gassing due to bubbles and messing with nutrients due to the carbon) than good. Try taking both of those out. Also, are you fertilizing at all?
You wanted tips. Here's my $0.02, take it for what it's worth. Start EI dosing, don't worry about nutrients. Instead, worry about proper CO2 production (since it's DIY) and delivery and light. Especially since you probably don't have a ton of CO2 in the tank, it being DIY, circulation is important -- that's the delivery aspect. Make sure all areas of your tank are getting water movement. One thing that can help you determine that is watching your plants. Are they all moving/swaying in the water? They don't have to be dancing around the tank, but if they're all moving, you're good. If you have a dead spot in the tank, that's a part of the tank that's not getting CO2. Something like a Koralia Nano is a good, fairly cheap way to fix this sort of problem. Also, as mentioned, it does look like you have a bit too much light over your tank. Is the fixture suspended or is it just sitting right on top of the tank? Is there a splash guard on it? You might also try adding some sort of stem. They can be beautiful and relatively fast growers, even in little light and will help you get a bit more plant mass in the tank. Something like Moneywort, perhaps.
These are just my suggestions, and I'm no expert. Like I said, take them for what they're worth.