Hi SF
Thanks for your reply. Amount of algae has definitely reduced since I upped the CO2 rate, but still a fair amount remains - otto's and SAE's are having a nice time though!
I have been thinking it's either diatoms or brown algae (same thing ?) as looking at most of the algae guides/stickies, they're the only ones that resemble it in terms of colour and appearance. Many articles I have read suggest that diatoms usually disappears on its own after a period but this has been present for quite a long time now and is quite 'crusted on'. It did spread over the walls and wood but I recently gave it an overhaul and a scrubbed it all off.
Some more tank info...
I am running 2x EX1200 on a 3ft 220L tank so I am rated over the 10x turnover guidelines. In both cannisters I have two trays empty, one with bio balls, the other with substrat pro topped with medium density foam, so I think filtration and flow should be adequate. I have been wondering if it would be worth taking out the individual pieces of foam and putting a course,medium,fine sponges in one of the empty trays to provide better mechanical filtration, any thoughts on this ?
I have but running the spray bars horizontal (towards the front glass) which are about 2" under the surface. I have just pointed them upwards now so I have more surface agitation, hopefully this will help. Fish stocking is 3x SAE, 6x Odessa barb, 6x Dwarf neon rainbows, 4 otto cats, 1 banded barb, fed minimally once per day. Approx 60% WC once per week. Filters cleaned out approx once per month.
C02 is coming on at 12:30 at high bubble rate, probably around 5bps, drop checker vivid green (fish seem fine) with 4x 39W T5 mounted about 150mm above water level coming on at 15:00 for two hours then two tubes going off at 17:00 leaving the remaining two on till 23:00 (8 hrs period). Wondering if it might be worth leaving the 4 tubes on for four hours instead of two ?
Nutrients wise I have been dosing EI:
18ppm N03, 30ppm K, 3ppm P04, 0.5ppm Fe, but have recently changed concentration to 30ppm N03, 35ppm K, 9ppm P04, 1ppm Fe.
My thoughts were to get C02 as high as possible as the fish are happy with (which I think I have about right), use unlimited EI nutrients. Then its down to light and good C02 distribution (not sure distribution of the bubbles is that good as tank is 20" wide - might add circ. pump to try and get better distribution at the back).
My Hottania palustris is growing tall but the lower leaves are often small and the bottom 2/3 of the plant goes dark, while the top 1/3 is nice and green and bushy (see pic).
Anybody spot any obvious mistakes or areas for improvements ?
Cheers
Paul