Long term diatoms (lights on only)

[greech]

I have read multiple threads on diatoms and read a couple of articles on diatoms but I still can't figure this out. Every morning my sand is bright white but every day I come home from work and my sand is dusted with diatoms. The dusting is a gold powder and not a mat like cyano or snotty like dinos. I do not see any on my rocks and I only need to wipe my glass about twice a week (glass is never really bad, I'm just a neat freak). Up until mid-April I had pretty much left my bed alone thinking it would go away on it's own. I would stir it up just a bit each week during WC's but nothing major. Since then I have been vacuuming the bed each week and lightly running my fingers through it each day in between. I have not observed any noticeable difference in the amount of diatoms from when I left the sandbed alone and now that I vacuum it. Some specifics on my tank and maintenance:

-40 breeder
-4x54W Sundial T5HO (8 hour cycle with 2 bulbs and 4 hours with 4 bulbs)
-2x Korailia Evo 1050 PHs
-Aquaclear 70 HOB filter running filter floss (changed 1 to 2 time per week) and Chemipure Elite (changed out every 2 months)
-2" max depth sand bed and less that 0.5" in some places. Sand was dry Caribsea Aragonite Select with a couple of cups of live sand from established tank)
-30ish lbs of LR (20 lbs or so was dry rock from BRS)
-3 fish (2 clowns and flametail blenny)
-Multiple LPS frags/colonies-
-Dozen Nass snails, 3 fighting conchs, tigertail cuke, 1 hermit, 2 medium mexican turbos

-20% water change every Satuday (never miss) using Brightwell's Neomarine mix
-Feed daily 1/8 cube of mysis or spirulina brine (drained) and a pinch of F1 or F2 flakes. Throw in a half dozen NLS pellets now and then as well. Food soaked in Garlic Xtreme
-SG 1.025, pH ~8.0 to 8.2, PO4 Non Detect, NO3 hovers from ND to 10ppm

Here is a pic of the tank:

You can sort of see the diatoms starting in these. About an hour after lights came on. They get much worse by days end but I have had the stomach to take a pic when it's at its peak.

Suggestions welcome!!!

 

[HighlandReefer]

If your pest is diatoms, many are golden brown in color, then the first thing one would suspect the presence of large amounts of silicates. Hopefully you are using rodi water for starting your tank, maintaining top-off and water changes. If you are using a rodi filter, then one should be aware that silicates are held loosely by the DI resins and when the DI resins become saturated, the first ions to be released are silicates and ammonia. The release can be sudden and in large quantities, which would cause spikes in diatom populations.

Randy provides more details in these articles:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria
http://reefkeeping.com/issues/2005-05/rhf/index.htm

Silica in a Reef Tank
http://advancedaquarist.com/issues/jan2003/feature.htm

 

[greech]

Thank you. I read the article from Randy today. From that article I took that some soluble silicates may be beneficial to our tanks but does that mean my concentrations are through the roof in order to maintain this constant bloom?

I am using RO/DI but I do not have my own filter. I buy my water from my LFS which is well respected in the area and I know several people that use their water and have no similar issues.

Am I wrong in thinking that a protein skimmer will do nothing for silicates?

I have a friend that owns a lab and can run some tests for me. After reading Randy's article I got some ideas on what to test for but is there anything specific I should request? Should I run silicates on both DT water and my RO/DI from the LFS?

 

[HighlandReefer]

GFO may help remove some silicate. I'll leave your question regarding silicates combining with organics and whether a skimmer would remove much to Randy. I don't know.

It is possible that your pest is not a diatom. It could be a bacteria or a brown algae also. One would have to look at this pest under a microscope to properly ID it.

As far as testing your water by a professional, Personally, I would be interested in your silicate, ammonia, phosphate and nitrate levels.

 

[greech]

Thank you for your help.

Any suggestions for a minimum detection level to request on the silicates?

 

[HighlandReefer]

The proper methods used to measure silica in a reef tank and interpretation of the results gets complicated. I would provide Randy's article to whoever you have completing the tests.

Randy explains this in his Silica Article noted above:

"Measuring Silica

Before going on to discuss silica in reef tanks, a few comments on measurements of silica seem worthwhile. In the context of organisms that use silica, we are only interested in soluble forms of silica, typically silicic acid and silicate. Ignoring the fact that there can actually be other soluble forms in certain situations, like extended chains or rings, the most important distinction that reef keepers need to be aware of is between tests that analyze for silicon, regardless of form, and those that analyze for soluble silica.

Tests that analyze for silicon, such as ICP (inductively coupled plasma) can include silica particulates (e.g., fine sand) in the result. Even with filtration, fine particles can evade removal. Consequently, it is complicated to extrapolate from an ICP measurement to a soluble silicate concentration. In Ron Shimek’s tests of aquarium water,29 for example, the technique chosen was ICP. Consequently, people should not interpret the values obtained, 1.8 to 104 mM (0.05 to 2.9 ppm Si = 0.11 to 6.2 ppm SiO2 ) as necessarily indicating anything about the dissolved silica concentration present in the tanks studied (except that the dissolved silica cannot exceed those numbers).

Similarly, in studies of salt mixes,30 the different forms may be an issue as well. In that case, the authors attributed differences between ICP and wet chemistry methods to the nature of the silicon present.

Tests that analyze for soluble silica, such as any of the kits available to the hobby, will only detect soluble forms. I recommend the low range silica test from Hach, Model SI-7, catalog number 22550-00. While the values obtained with such kits may not be comparable to those obtained by other methods, they are suitable for understanding how much dissolved silica is present and available to organisms in tank water, and in other aqueous solutions, such as tap water."

 

[greech]

Admittedly, much of that is over my head. Good suggestion to provide the article. Thanks again!

 

[HighlandReefer]

Your welcome and good luck in gaining control of your pest.

 

[bertoni]

It's possible that you are seeing cyanobacteria. If you have access to a microscope, that's one way to tell. GFO will remove silica after all the phosphate is gone from the water. If you're using a good RO/DI filter, the only likely suspect for adding silicate would be the salt mix. You could try measuring the level in some freshly-mixed saltwater.

 

[greech]

I have seen cyano and it's not like that at all. It's very gold/bronze in color and dusty (will not hold together at all). I planned on having my water tested for silicates and silica acid in both freshly mixed water and my DT's water.

 

[Randy Holmes-Farley]

Maybe the LFS water wasn't as good as it usually is. For example, if the DI began to deplete, silicate may be especially high in the effluent.

 

[greech]

Maybe the LFS water wasn't as good as it usually is. For example, if the DI began to deplete, silicate may be especially high in the effluent.

I considered that but I know quite a few people that use both their fresh and premixed SW and no one seems to have this issue. Could one bad batch of RO/DI cause this problem to persist for almost 9 months?

Other than the less than desireable appearance of my sandbed in the afternoon hours, I don't see any other negative impacts. Maybe I should just continue to leave things be for a while longer?

Would you consider my lack of skimmer to be a/the contributing factor here?

 

[sslak]

Growing during the light cycle and dying off at night is the trademark sign of dinoflagalletes. (spelling?)

Look into it.

 

[greech]

Growing during the light cycle and dying off at night is the trademark sign of dinoflagalletes. (spelling?)

Look into it.

Understood and believe me I have. There is no resemblance to any dinos I have seen. Just tiny grains of bronze/gold in the sand. No stringy, oozing, snot like substance with air bubble clinging to it. There has been no change to the amount or their appearance since they showed up months ago. Thanks.

 

[DeepReefExotics]

I have the exact same issue but no idea what it is either. It is also completely gone within 1-2hrs of the lights out and back within 1-2 once they are back on.

 

[greech]

I have the exact same issue but no idea what it is either. It is also completely gone within 1-2hrs of the lights out and back within 1-2 once they are back on.

Is the dusting limited to your sandbed only?

 

[DeepReefExotics]

Yes, they are limited to just the sand which is Cora Pet #3.

 

[Randy Holmes-Farley]

Can you list all foods and additives you use?

Maybe we can spot something that might contain silicate.

What kind of sand do you have?

 

[DeepReefExotics]

I use a natureef denitrator, bubble king 250 rdII for filtration. As far as additives i feed frozen PE mysis, seaweed for my tangs but only dose BRS 2 part and kalk.

I have started using probido bio digest to try and fix the issue but started dosing this after the issue had already begun.

I ran bio pellets for a few months but took it off line as i didnt notice it was taking the care of the problem either.

 

[greech]

DeepReefExotics...Out of curiosity did you happen to use any dry rock in your system? If so where did you get it and did you cure it or clean it before you added it to your system?