I dont like the idea of a wet/dry system In my bedroon and ive heard they are nitrate factory
Many fallacies abound in this hobby. Nitrate Factory? No more than any other type of filter, in fact I would argue much less due to the ease of access and routine maintenance. Ever see how much waste comes out of a canister filter after two months? Nitrates are usually not harmful unless they reach extreme levels. Remember, we dose nitrates in planted tanks. Plants feed on nitrates. I doubt you would ever see dangerous levels of nitrates using a wet-dry/trickle filter on a planted tank assuming you know what you are doing. I believe the reef people are the folks that are more concerned about filters being "nitrate factories", and rightfully so, not the planted tank people. For me, the benefits of a wet-dry/Trickle filter far outweigh any cons. When someone can come up with a more efficient way of filtering, then perhaps I will jump on board. Until then, if it is good enough for Tom Barr, it is good enough for me.
I have a wet/dry on my 125 planted Discus tank The hightes my Nitrates get is around 25pp I do 50% w/c once aweek and my plants and fish are happy.I just Lava rock/Biohome for my Bio-Media keep up on your w/c and youll be fine.
I have a 20L sump with similar set up, as far as compartments and baffles, my only regret is I didn't make the return pump compartment larger. It holds about 25%, I would recommend a least 30% or more if you are going with an open top.
I also run a wet/dry Tom Barr style, I would be careful with section 5 don't put heaters there as evap will show in that section and your heaters could dry out! Also very important to be able to clean the bottom of the entire sump with the wet dry I just clean my filter pad on top and the detritus that accumulates on the bottom of the sump. Much easier than a canister if setup right. Also tried the fw Refugium thing doesn't really help and is hard to clean.