300 gallon FOWLR lighting, cyno, flow, and algea scrubber Q's, Help please!


New member
This is a FOWLR set up. I figure ill post this here b/c i only have 8months exp in the hobby.

Tank and equipment:

300 gallon marineland DD 72"x36"x27" with glass tops
75 gallon sump with live rock about 1500gph running through it.
Super Reef Octopus 5000 cone skimmer
BRS carbon reactor
21"x17" algae scrubber with 4 23 watt cfls (set up two weeks ago)
2 Koralia 1400gph power heads
2 25 watt 36inch fluorescent fixtures for the main display lighting. Yes I have 50 watts of lighting for a 300 gallon tank lol.
150lbs live rock
75lb aragonite sand

Tank parameters:

I am using RO/DI water, however i wasnt for the first month.
Specific Gravity: 1.022
Nitrate: 30ppm
Phosphate: .7ppm
Ph: 8.0
Carbonate Hardness: 8.2dKH
Calcium: 350ppm
Nitrite: 0ppm
Ammonia: 0ppm

Tank Residents:

7" six line grouper
4.5" Niger trigger
3" clarkii clownfish
6" sailfin tang
7" hippo tang
4.5" cream angelfish

The tank has been set up for about 8 months and ever since it's been set up I've had serious cyno problems.


I have a total flow of about 4800gph is this enough?

Should I add two more 1400gph koralias?

There are areas were detritus sits on the sand but if I bring the power heads closer they just blast the SAND and detritus away, are any tips and tricks to power head placement?

Is it possible the poor display tank lighting is causing the cyno?

If I get the 72" NOVA extreme pro lighting system for the tank will the improved lighting cause GHA to grow in the tank and not on the scrubber (the scrubber has 4 23 watt cfls for a total of 92 watts)?

Will the NOVA lighting system encourage coraline algae growth?


As you can see the cynos all over everything


In the pic above you can see the more cyno. Also I cant lower the power hear in the far right pic because it starts making sand tornados. Any suggestions?


And above is enven more cyno in the sump i just vacumed it out today


Above is the algae scrubber when first started. There is much more growth now


Full tank shot, sorry for the bad photography. You can see the cyno is having a party in the sump. Better there than in the display!

Thanks in advance!!


Team RC
I like between 10 and 20 times the DT volume for flow in a FO tank, so you are right there. Additional flow may help, but I don't think that is your main problem. As far as the sand goes, it take experimentation to find the right placement to eliminate low flow spots while preventing sand erosion. I would try the koralias up higher in the tank aiming down towards the middle of the tank bottom and then adjust accordingly. I would think your lighting is your main problem. You don't give the bulb temperature (color), but as bulbs age they tend to shift color towards the 5K range, which is perfect for algae growth. I think even if your lighting didn't cure the algae issue, the color it would bring out in your fish would make it worth the expense. The proper lighting will not increase the algae and would likely help. Yes the new lighting will increase coraline algae growth (like it or not). Your phosphates are high also, perhaps a GFO reactor would help.


New member
color temp for the display bulbs are 8000K and about two weeks old. Im gonna try moving the power heads up and aiming them down. Seems like a good idea


New member
In my limited experience I would say that your phosphates are too high and is causing your cyano issue. Water changes, less feeding and GFO should help.