Brown Slime Algae question

[Ted_C]

I've been having an issue with brown slime algae for a few months now. I've been set up and running since October last year.

The tank is a quarantine / eventual frag tank. so it has frag racks and lots of PVC for hiding.

It's 150 gallons with high flow (turnover is around 9000 gallons per hour into the sump and the maxspect gyre is running at 60%). 1.5" sand bed, 2x 8x8x4 ceramic blocks. around 8 pounds of live rock rubble are in the main display - in pod hotels. 2 felt filter socks are changed out every other day. Performing water changes every 8 days at 25 - 30 gallons. Cleaning the glass every 8 days during water changes. NYOS 220 Quantum skimmer - skimming wet

Livestock: 4 Mexican Turbo, 3 Trochus, 4 red leg / blue leg hermit, 2 skunk cleaner shrimp, 2 bangaii, 2 clown, 1 bellus angel, 3 firefish, 1 blue neon goby

The question is: the brown slime algae only grows on the plastic surfaces. The frag racks, the pvc, the overflows, and the returns. the sand bed is still pearly white and the live rock rubble doesn't have a bit of algae on it. It eventually grows on the glass - requiring a good scrubbing. It grows on the silicone sealant for the tank.

Any ideas why it doesn't grow on live surfaces? Might I benefit by transferring the biomedia blocks into the display rather than having them sit in the sump?

 

[rogergolf66]

Phosphates leaching from those plastic materials?

 

[TampaSnooker]

^^^ that would be my assumption

 

[Ted_C]

that's sup rising to me. I didn't realize this was a possibility. I'll do some additional research.

Thanks for the input.

 

[TampaSnooker]

You should find plenty of info - mostly anecdotal though. White eggcrate is most often implicated - the blends of recycled material that typically make up the plastic vary a lot more with the white than black eggcrate.

 

[rogergolf66]

You should find plenty of info - mostly anecdotal though. White eggcrate is most often implicated - the blends of recycled material that typically make up the plastic vary a lot more with the white than black eggcrate.

Personal observation when I use acrylic racks the algae stops pretty quickly, the white egg crate took a long time to stop having algae problems. The black also had some but stopped after a few months. Just my personal experience. No scientific data to back it up

 

[TampaSnooker]

Personal observation when I use acrylic racks the algae stops pretty quickly, the white egg crate took a long time to stop having algae problems. The black also had some but stopped after a few months. Just my personal experience. No scientific data to back it up

My experience is the same. Sometimes we can forego the science when the solution is obvious...

 

[Ted_C]

I've thought about re-configuring this setup to use acrylic instead of PVC / egg crate.

Do you think the phosphate leaching would ever mature to the point where it would stop? The fact that the overflows still get the brown slime algae is what steers me to say no - since this tank is 7 months in the running for me and was run for i don't know how long with jmonks.

 

[TampaSnooker]

I have never seen much issue with PVC leaching - it generally gets covered in coralline. White egg crate has always been difficult for me. Poor flow dynamics in and around the grid combined with phosphate and whatever else leaching is a good recipe for algae. Black egg crate will collect algae as well, but I think that is due to flow dynamics and accessibility to grazers. Recently, I've received some frags growing on black acrylic and nothing sticks to that except coraline. Downside to using it for racks would be complete blockage of vertical flow around specimens.

 

[Ted_C]

I think I've solved my problem by moving the ceramic blocks into the main display from the sump.

The main display only had a few pounds of rock rubble and a 1 inch sand bed. I do believe I had localized nitrates building up in the main display because of the lack of adequate biological filtration. Despite the high flow and turnover - the egg crate and other non-biological surfaces allowed disruption of the flow so the nitrates could be higher in certain areas.

With the blocks in the main display again - the algae has slowed it's growth - allowing the meager cleanup crew to keep it in check.

My next steps will be to beef up the cleanup crew some more to keep it in line with a cleaner reef and wait on the coralaine to start growing.