Return Flow vs Tank Size and the effect on scrubber efficiency

[mess7777]

I do like my scrubber, it does grow some algae. However, it seems to be slow and just doesn't get the job done. My nitrates got to zero and are now staying there, but my phosphates just won't get under control. I had them all the way down to .03, but as of yesterday they bounced back up to .18. This is 2 weeks after a cleaning and also with 1.5 cups of BRS GFO running.

It seems like the GFO is going all the work and exhausting itself quickly. I can't afford this, that's for sure...if I can't figure out how to get the scrubber to help I'll have to get a skimmer...so be it.

I did start thinking about my turnover rate and that it is possibly a part of the problem. My return pump is turning over somewhere around 120 gph on my 90 gallon tank. Maybe that's just way too low to get enough tank water exchanging with the sump to clean it. The live rock in the tank is processing the nitrates...but the phosphates just aren't getting down to the sump to be dealt with?? Looking for opinions on what increasing this flow would do as far as the effectiveness of the scrubber? Most tanks I see have a much higher turnover than what I am running, that's for sure. I would think most folks on a 90g turn over 400-500 gph?

I would love to improve my lighting...current a 40sq in screen with 2 23 watt CFLs. This should be enough, but it seems many on here seem to think lighting increase would help it run better. Leds would be cool, but my space under the tank is limiting (only 21" clearance with an 18" high sump). A nice enclosed ATS with LEDs just isn't going to happen.

Thanks for offering your opinions on this water turnover question....I gotta win this phosphate battle without using $5-10 of GFO every 2 weeks!

[iiluisii]

I dont think is you return cause its keeping up with nitrates. That the same problem I had and most people no nitrates but detectable phosphates. Im trying something at the momment but it involves using bio pellets carbon dosing. At the moment my scrubber is nott installed. Im about to install it soon and what im doing is im gonna try to force the scrubber to rely on phosphates to grow since all my mitrates are gone because of the pellets. And by no means im an expert im just trying something an other reefer tried and its working. People on this site will tell you that it wont work but they are just going from what they think and not by experience. Look at advance aqiarist on line and search for the article on paul b 400 gallons tank and you will see what im talking about

[SantaMonica]

If your scrubber is growing, it has plenty of turnover. One 23w bulb on each side of a 40 square inch screen is bare minimum; you could start by doubling that.

[mess7777]

I tried the next size up CFL but it won't even power up in the socket I currently have. I don't know if they even sell a reflector type light that would support it, since I only ever see 1 model at the hardware store. Maybe I'll have to suck it up and try one of the standard socket LED bulbs with red/blue like Ace tried out. Just wish that experiment wouldn't cost me $50.