Diatoms and Circulation

[Martyt1]

Question,, I am fairly new to the whole saltwater scene and I have had to do a lot of learning the hard way which has gotten quite costly I might say. I am currently experiencing a fairly heavy diatom bloom and It will NOT go away. This has been going on for several months and it looks really ugly.. My question is , my tank is 55 gal and my 2 powerheads are only 600 gph ,, is it possible that I don't have enough flow in my tank? All levels look fine and fish are thriving, I even have a recent appearance of a COLONY of brittle starfish which I have NO IDEA how I got them. Unfortunately they aren't helping things a lot as they are all babies. Any thoughts or ideas would be greatly appreciated.

[AirForceAquariu]

This forum is for the discussion of the hobby on the enviornment etc.

When I think about it the name could be a tad confusing. Try "New to the hobby" and they can help you out.

Short answer, all tanks go through phases of diatoms, cyano, Green Hair Algae (GHA) etc in their infancy. Give it time and keep up maintenance! Also keep your nitrated down with water changes.

[billsreef]

This thread has been moved to the current forum....

[Jritter02]

I believe I read somewhere that for a reef tank you want 50-60 times tank volume to be circulated. That's for reef. And I believe fish was somewhere around 30-40. I just set up my 90 and I have around 2500gph worth of flow cycling my tank. I have another 1600gph powerhead but I feel like that might be a little too much by going off just watee movement in the tank. Once I'm done cycling abd have fish and corals in the tank I might put it in the tank and see what we are lookin like.

[wcarterh]

That is low circulation flow.

Also as AirForceAquariu said, it's normal. But they are pulling food from somewhere. What are your tank parameters?

[gone fishin]

A 55 can be hard to get good flow if you have a lot of rock work and due to the narrowness of the tank. You could try to rearrange your power heads, if that does not work then I would probably bump up the flow to somewhere around 1000gph. Unfortunately there is not a hard rule for flow. This is due to everyone's tank having different aquascaping lay outs. Good luck.

[shesacharmer]

Definitely low flow. The diatoms should easily blow off the rock with a turkey baster like dust. If it comes off in sheets you may have a different problem. What color is it? Can you post a picture? It's not unusual for diatoms to transition straight into a different algae or bacteria issue right in front of an untrained eye. You definitely don't have enough flow but diatoms will remain until all of the silica is used up in your tank. What kind of sand did you use?

[CuzzA]

Originally Posted by Martyt1

Question,, I am fairly new to the whole saltwater scene and I have had to do a lot of learning the hard way which has gotten quite costly I might say. I am currently experiencing a fairly heavy diatom bloom and It will NOT go away. This has been going on for several months and it looks really ugly.. My question is , my tank is 55 gal and my 2 powerheads are only 600 gph ,, is it possible that I don't have enough flow in my tank? All levels look fine and fish are thriving, I even have a recent appearance of a COLONY of brittle starfish which I have NO IDEA how I got them. Unfortunately they aren't helping things a lot as they are all babies. Any thoughts or ideas would be greatly appreciated.

Marty,

Several months is a long time to still be experiencing diatoms. Diatoms feed off of silicates. Two common mistakes new hobbyist make are using play sand and starting/using unfiltered tap water which creates long term diatom problems. So what did you do? If neither than you may just have been unfortunate and your marine grade sand and/or rocks simply had a lot of silicates in them. Or it may not be diatoms at all. A few quality pictures under white light will help.

Nevertheless, if it is in fact diatoms the only way to remove them is to keep up on your husbandry. Frequent water changes, a good clean up crew (micro brittle stars aren't a solution... mexican turbos, trochus, large cerith, and nassarius snails will help) and most importantly the use of GFO in a reactor. These 3 combined methods will export the silicates; however, it may take some time depending on how much silicate is present in your system. Also, if the diatoms are covering your sand bed a good sand sifting goby like a Diamond Watchman will keep the sand bed clean.

As far as flow, you likely need a lot more. You want water passing over your sand bed strong enough to aerate it, pull the silicates out, and keep any detritus suspended in the water column, yet not too strong that it's blowing the sand bed around the tank. 600 gph on a 55 gallon tank will likely not accomplish this. A good rule of thumb is your return should be 10x tank volume so on a 55 gallon you're looking at 550 gph (don't forget to calculate head loss) and about 40x tank volume in powerhead flow. So about 2,200 gph. With such low flow in your tank it could also be cyano that your experiencing, again post some picture first before we get into that discussion.

[tmz]

Diatoms feed on nutrients inculding phosphate and nitrogen. They need silicate for their exoskeletons . GFO binds phosaphte , metals and silicate.As the diatoms wane other nuisance algaes and cyanobacteria may appear ,feeding of them and the nutrients. Some sponges also need silicates as do some other ogranisms.


GAC( graulated activated carbon) and skimming are helpful in removing organics and the nutrints they hold.

Flow may keep things moving but won't reduce anything.
Too much flow can harm corals by keeping them closed or tearing their flesh. FWIW: I rely on exchange flow rates ( sump to tank) of 5x water volume and total flow rates ( exchange plus internal water movement via power heads ,etc) of 60 to 100x water volume for sps tanks and 20to 30x for lps and leather tanks). Internal flow is alternating and turbulent not laminar in my tanks.