I've been through this a bunch of times with a lot of people and we can't seem to pinpoint the problem.
I use only RO
water (it is pure, it tests 0ppm tds
I do a 25% PWC
weekly with instant ocean reef crystals salt.
My sump consists of overflow box, filter sock, protein skimmer (hob
reef octupus), then fuge with sand (not a deep sand bed), rock (again, base rock made live), chaetomorpha, then i have my return section with a bag of carbon in it.
no sponges anywhere except for a small filter floss that i keep in my sump in case i need an emergency qt/hospital tank
I have about 50lbs of rock (55g) and about 5 in the fuge. It's very high quality porous rock from reefcleaners
I have a large cleanup crew (and as far as i can tell they are not dead).
On a positive note the nitrates have dropped down to about 20ppm but they seem to stay there.
I need to try a very large water change or several smaller water changes and see if once I get rid of it it will stay at undetectable levels.
But, back on topic, is it a good idea to have a reactor anyways - even if not for nitrate removal?
How effective is a mesh bag full of carbon/gfo
versus a reactor? (for the record, i don't need the carbon and I haven't ever tested for phosphates yet)