Dosing silicate and using GFO

[Apagador]

I'd like to try dosing silicate to save my shrinking sponges, but I have a pretty bad dinoflagellate problem that I'm trying to fight with GFO (and high pH, reduced photoperiod, siphoning it out manually and reduced feeding of the tank..).
If I understand correctly GFO binds silicates as well as phosphates so using it and dosing silicate seems to be pretty useless? Should I just forget about silicates for now and let my sponges shrink to nothingness? Could adding silicate help with my dino problem by helping diatoms compete for the available nutrients so that the dino's would starve? Wishfull thinking probably, but I'm pretty desperate at the moment.

 

[Boomer]

First have you tested for silica, as you may not even need it. Sponges can be difficult to raise and have nothing to do with low silica. Second, high or normal silica will have little impact on Dino's. If anyhting the release of toxins from the Dino's may be affecting the Sponges. Lastly, how are you bring about this high pH, with Kalk I hope ? The goal here is to try and have a high pH with low Alk, so they are starved so to speak of CO2. If you are using some buffer like baking soda or wshing soda the Alk will be high also, which will also yield a high CO2.

 

[Apagador]

I have not tested for silica yet so it's true that I don't know my tanks silica levels. However Randy makes it seem like silica is pretty rapidly depleted in a normal reef aquarium in his article SILICA IN REEF AQUARIUMS . It also makes it seem like sponges do require silica to thrive. I'm going to get a silicate test kit as soon as I can.

I'm using activated carbon to trap the released toxins from the (hopefully dying) dinoflagellates and I change it regularly.

I have been using kalk to keep my pH high. I haven't noticed any difference in the dinoflagellates returning speed after siphoning them out, so I'm about to stop using it. Everything is covered with calcium deposits now so it's starting to be a bit frustrating.

 

[Boomer]

OK and the Kalk trick does not always work just so know.

Althoguh silica is limiting for diatoms and some sponges you will still seem them grow in tanks even when you can not detect any silica. Rarely, IMHO, is it silica that brings about the death or demise of sponges. It is usually lack food or water quality, unless you are dealing with Sycon sponges, like Scypha sp, which will grow in a snow bank

 

[Apagador]

I know that using kalk does not always work. I'm so desperate with the dino's that I was willing to try it anyway. I guess I'm back to trying to starve them out. Not sure how I could do that without starving everything else in the tank at the same time..

I guess I should just forget silicate additions for now at least if it's of no use as you say.

I just hate these dinoflagellates..

 

[Randy Holmes-Farley]

I agree that there is some sense of running in a circle with dosing silicate and using GFO, but if I had sponges that I was concerned with, I'd probably continue to dose some silicate and if algae is a problem, I might also continue GFO.

I also agree that sponges may well die for reasons unrelated to silicate, and the benefit of dosing for large sponges has not been clearly demonstrated in reef tanks (although I do not know if anyone has actually tried to show it).

 

[Apagador]

They could hardly be called large sponges. Just some sponges that happened to come with the live rock, but I have been trying to keep them alive since I find them fascinating.

Maybe I should just forget about the sponges and try to get rid of the dinoflagellates as best as I can. Sometimes I wonder if it's worth the trouble. The dino's just keep coming back no matter what I do..

Thanks for the help.

 

[Randy Holmes-Farley]

Sponges that come with live rock often die, especially larger ones, but the few that do survive often thrive, and I have many that have grown from unnoticed on live rock to cover substantial areas of the rock in more shaded areas. I do believe that they grow more in my system than they would without any silicate added, but I can't prove it.

 

[Boomer]

So, my next question would be are these silica based sponges or calcareous based sponges You guys got any pic for me to ID

 

[Randy Holmes-Farley]

I've not taken pictures of any of mine.

 

[Apagador]

 

[Boomer]

That blue one looks like a encrusting Collospongia sp. and there are many varities, which have Silica based Spicules. The second pic is of one of Leuconia sp. sponges, which are the most common common calcareous sponges you see in a reef tank along with the "pineapple/ Q-tip" sponges, also calcareous based Spicules. Often sumps are covered with these.