Silicate dosing to combat dinoflagellates

[RobertK]

I have recently started dosing 40% sodium silicate as part of an ongoing effort against Amphidinium and Ostreopsis dinoflagellates in my tank. I've read as much as I can on this subject and it seems that maintaining a silicate level of 1-2 ppm is a reasonable target range. I bought a Hanna silica checker, which has an upper detection limit of 2 ppm (as SiO2). I started with the dose in Miami Reef's dosing chart and it got me to the middle of that range, but it was below 1 ppm the next day and completely depleted back to the baseline level (~0.2 ppm) in 2 days. So it appears I need to dose it daily or every other day to keep it in that range. Does that sound right? Thank you!

 

[Dan_P]

I have recently started dosing 40% sodium silicate as part of an ongoing effort against Amphidinium and Ostreopsis dinoflagellates in my tank. I've read as much as I can on this subject and it seems that maintaining a silicate level of 1-2 ppm is a reasonable target range. I bought a Hanna silica checker, which has an upper detection limit of 2 ppm (as SiO2). I started with the dose in Miami Reef's dosing chart and it got me to the middle of that range, but it was below 1 ppm the next day and completely depleted back to the baseline level (~0.2 ppm) in 2 days. So it appears I need to dose it daily or every other day to keep it in that range. Does that sound right? Thank you!

Seems like a reasonable conclusion

 

[Randy Holmes-Farley Verified Community Expert]

Diatoms, which are the reason to add silicate in relation to dinos, rapidly deplete added silicate. :)

 

[RobertK]

Diatoms, which are the reason to add silicate in relation to dinos, rapidly deplete added silicate. :)

Yes I am seeing evidence of that! I posted this because I saw it recommended in a couple of places to dose silicate weekly, but it appears more frequent dosing is required to maintain a level >1 ppm.

 

[Randy Holmes-Farley Verified Community Expert]

Yes I am seeing evidence of that! I posted this because I saw it recommended in a couple of places to dose silicate weekly, but it appears more frequent dosing is required to maintain a level >1 ppm.

Yes, I found that it rapidly depleted. Maintaining a specific level is not the goal. Diatom growth is, so dosing is needed, but not a specific maintenance level.

 

[RobertK]

Yes, I found that it rapidly depleted. Maintaining a specific level is not the goal. Diatom growth is, so dosing is needed, but not a specific maintenance level.

Yes but if we are trying to accelerate diatom growth above what occurs at baseline silicate level (0.15-0.2 ppm in my tank according to Hanna) don't we want to maintain a level greater than baseline?

 

[Randy Holmes-Farley Verified Community Expert]

Yes but if we are trying to accelerate diatom growth above what occurs at baseline silicate level (0.15-0.2 ppm in my tank according to Hanna) don't we want to maintain a level greater than baseline?

I don’t know what baseline really means. I expect silicate will deplete below reliable levels of detection as diatoms consume it. But I’m not saying it is not worth dosing repeatedly. In my old tank I dosed silicate once or twice a weeks for years to supply sponges.

 

[RobertK]

I don’t know what baseline really means. I expect silicate will deplete below reliable levels of detection as diatoms consume it. But I’m not saying it is not worth dosing repeatedly. In my old tank I dosed silicate once or twice a weeks for years to supply sponges.

In this case baseline means the silicate level before I started dosing.

 

[Randy Holmes-Farley Verified Community Expert]

In this case baseline means the silicate level before I started dosing.

I understand, but I’m not sure it is real. In any case, I assume it is used fast, and that, while ok to keep dosing, is not necessary to maintain that level constantly.

 

[RobertK]

I understand, but I’m not sure it is real. In any case, I assume it is used fast, and that, while ok to keep dosing, is not necessary to maintain that level constantly.

OK, thanks Randy!

 

[JonasRoman]

For me the main question, and my curiosity now is if this will get rid of the dinos. Please update this thread by that info. There is so many treatments and many doesnt work, maybe some work, so I would like to gain more experience for just this Si method. Will follow this. I guess you will observe now from day to day?

Jonas

 

[Dan_P]

For me the main question, and my curiosity now is if this will get rid of the dinos. Please update this thread by that info. There is so many treatments and many doesnt work, maybe some work, so I would like to gain more experience for just this Si method. Will follow this. I guess you will observe now from day to day?

Jonas

You probably won’t learn much from anecdotal evidence.

The few papers I have read lead me to accept that diatoms under certain circumstances can outcompete dinoflagellates. The trouble with this assertion supporting the dosing of silicate to grow diatoms and get rid of dinoflagellates is that we don’t know under what conditions diatoms dominate, which diatoms can dominate which dinoflagellates, are the right diatoms present in the aquarium, how much silicate, nitrate, ammonia, phosphate and trace elements are required, etc. We only have anecdotal data that it works.

This is just another hobby home remedy and like many home remedies, it does little or no harm, so, it is still advocated.

 

[RobertK]

For me the main question, and my curiosity now is if this will get rid of the dinos. Please update this thread by that info. There is so many treatments and many doesnt work, maybe some work, so I would like to gain more experience for just this Si method. Will follow this. I guess you will observe now from day to day?

Jonas

Yes of course I am observing day to day and I'm happy to provide updates, but as Dan said that would be just more anecdotal evidence which we already have an abundance of. I wanted to measure silicate levels and have a target level in order to introduce some sort of methodology to my dosing, but realize there is no evidence for doing so.

In my case I have both Amphdinium and Ostreopsis on both the sand and the rocks, which may be complicating matters. On the sand the Amphidinium predominates but there are some Ostreopsis seen there as well, and the reverse is what I see on the rocks. From what I can gather, silicate dosing is mostly purported to help with sand dwelling species such as Amphidinium so I don't know if this will work. I'm already running a UV sterilizer in the sump and might be moving it to the display soon if the problem persists. I was using a UV sand sweeper as well, which helped temporarily, but am pausing that now as I don't want to kill the diatoms that I'm trying to cultivate. NO3 has been running 5-10 and PO4 0.2-0.3 with Hanna testers.

I've only been dosing silicate for a week but am already seeing more diatoms on the sand, including a type I have not seen before, so maybe the silicate is doing something. But there are still dinos there too, and so far no obvious change on the rocks.