Silicon Source?

[jimfish98]

Looking for ideas on where silicon could be coming from. I have two tanks, a 130g and a 25g, and two RODI units to fill my RODI container. ICP tests came back with no silicon in either RODI units water. My 130g came back with 113.1ug/l for Silicon and was above ideal but still normal. My 25g however came back at 294.7ug/l. Both use the same water source, same salt mix, same foods, same lights and lighting schedule. The 130g is dosed with AFR, Microbacter7, and Amino Organic while also running a protien skimmer. The 25g only gets the amino organic and has no protien skimmer. Both have fleece rollers. The 130g gets a 20% water change biweekly, the 25g gets a 25% water change biweekly.

Curious as to how silicon is getting in and then how it can build up in one system but not the other. I have added an extra water change in this week to lower it and correct some other things based on the ICP results, as well as added a Phosguard to absorb the silicon...but I would rather solve it at the source instead of playing catch up.

 

[Randy Holmes-Farley Verified Community Expert]

Do you have problematic levels of diatoms? if not, significant SI is no concern.

I regularly dosed silicate to higher levels than you report and think it was desirable.

https://reefs.com/magazine/silica-in-reef-aquariums/

 

[jimfish98]

Tank has been up and running for almost 2 years, never had a diatom issue even in cycling. I suspected it was high though as my pineapple sponge population in the AIO middle chamber was growing significantly and it was starting to show under my rock where its dark (can see as its bare bottom). Could care less about the ones in the rear chamber, but it would be nice to keep it at a level where I don't see an explosion in my tank.

 

[Randy Holmes-Farley Verified Community Expert]

Tank has been up and running for almost 2 years, never had a diatom issue even in cycling. I suspected it was high though as my pineapple sponge population in the AIO middle chamber was growing significantly and it was starting to show under my rock where its dark (can see as its bare bottom). Could care less about the ones in the rear chamber, but it would be nice to keep it at a level where I don't see an explosion in my tank.

My understanding is that pineapple sponges (genus Sycon) do not use silicate, but rather make calcium carbonate (calcite) internal spicules. I'd ignore the SI.