Reducing Silicates (Without GFO?)

[tmb22]

I've got a bit of a head-scratcher in terms of how I proceed with a slight silicate problem in my tank. I recently got back an ICP test from Triton which indicated I had high Silicon in the system (360 micrograms/liter), which normally I wouldn't really worry about as silicates aren't normally a big problem as I understand... But I have what I believe to be diatoms dusting the glass (cleaning daily, returning daily) and fluffy brown diatoms attaching themselves to the rockwork.

I purchased a silicate test kit from Salifert after getting the results from Triton so I could find the source of the silicates, but the tank registered a 0.00 which is disappointing because I know there are excess silicates in the water from the Triton test.

As I understand, GFO can be used to reduce silicates, which is great, but I'm currently trying to RAISE PO4 (from 0.00-0.01), so I feel using GFO would work one problem against the other. Any ideas on a workaround?

Possible causes of silicate source:
-BRS dry rock (cured in saltwater for about 3 months prior to adding fish/corals)
-Instant Ocean salt mix (standard, not Reef Crystals)
-RO/DI filters (all filters, including DI and membranes) replaced not more than 2 months ago, producing 0 TDS water, so pretty sure it's not that. Color-changing resin still mostly blue.
-Tank has been running for 8 months.

Let me know if I can add any other data that might be helpful. Ideally I'm just looking to find a way to use GFO (or any other silicate removal strategy) that won't deplete PO4 completely. I'd also obviously like to find the source of the silicates, but find it difficult if I don't have a reliable test kit for it.

 

[XNavyDiver]

I have the same issue and same rock as you. Except my po4 shot up after eliminating a small gha issue. I still get that daily brown dusty diatom stuff on the rocks and glass. As you're a few months ahead of me, looks like it will stay with me for some time longer.
I'm not sure about the silicate thing. Is this something common for brs dry rock?

 

[tmb22]

I have the same issue and same rock as you. Except my po4 shot up after eliminating a small gha issue. I still get that daily brown dusty diatom stuff on the rocks and glass. As you're a few months ahead of me, looks like it will stay with me for some time longer.
I'm not sure about the silicate thing. Is this something common for brs dry rock?

I'm really hoping it's not the rocks, but I really don't see another likely source. It would be great if I had a reason to switch from Instant Ocean to something else, but I don't think the salt is the culprit, nor the RO/DI system. I haven't seen any trend that BRS dry rock commonly leach silicates, but I'd be interested to know if others with the same rock are experiencing the same things.

 

[120reefkeeper]

https://www.sera.de/en/product/sera-marin-silicate-clear/

 

[Randy Holmes-Farley]

https://www.sera.de/en/product/sera-marin-silicate-clear/

That is likely aluminum oxide, which is also a phosphate binder.

I'm not aware of any chemical media we use that binds silicate and not phosphate.

 

[120reefkeeper]

That is likely aluminum oxide, which is also a phosphate binder.

I'm not aware of any chemical media we use that binds silicate and not phosphate.

IMHO it did work for me with binding silicate. I verified this through ICP Analysis. Can't say for sure if it took some phosphate out with it or not , but it didn't appear to do so . My phosphate did not drop dramatically from one ICP test to the next, although the silicate most certainly did.

 

[Larry L]

FWIW, I've seen a few other recent reports of Triton results (including my most recent results) that unexpectedly came back with high silicates - kinda makes me wonder if there's something going on with that at their end...

 

[tmb22]

That is likely aluminum oxide, which is also a phosphate binder.

I'm not aware of any chemical media we use that binds silicate and not phosphate.

I thought this was the case, but good to know for sure. Thanks Randy.

IMHO it did work for me with binding silicate. I verified this through ICP Analysis. Can't say for sure if it took some phosphate out with it or not , but it didn't appear to do so . My phosphate did not drop dramatically from one ICP test to the next, although the silicate most certainly did.

Interesting. Did you use it in a reactor? Just one box's worth?

FWIW, I've seen a few other recent reports of Triton results (including my most recent results) that unexpectedly came back with high silicates - kinda makes me wonder if there's something going on with that at their end...

Hmm, that's a bummer. I really hope that's not the case. I think most people just assume the test results to be fact, so that could definitely cause some problems! I'm hoping the brown algae I'm seeing is a correlation to high silicates. Strange that my Salifert kit isn't picking any silicates up though. Maybe the water has used up all the silicates as diatoms for now, making the reading 0.

 

[reeferfoxx]

How much silicate was present on the triton test?

 

[tmb22]

How much silicate was present on the triton test?

359 micrograms/liter (.359ppm). Triton's setpoint is 100 micrograms/liter, and I'd be perfectly happy with a reading of 0.00 as well.

 

[120reefkeeper]

I thought this was the case, but good to know for sure. Thanks Randy.



Interesting. Did you use it in a reactor? Just one box's worth?



Hmm, that's a bummer. I really hope that's not the case. I think most people just assume the test results to be fact, so that could definitely cause some problems! I'm hoping the brown algae I'm seeing is a correlation to high silicates. Strange that my Salifert kit isn't picking any silicates up though. Maybe the water has used up all the silicates as diatoms for now, making the reading 0.

I used it in the supplied mesh bag and no i ended up using 2 boxes.

 

[Volcmreefer]

I had high silicate levels as well with my Triton results. Just added a SilicaBuster DI membrane to my RODI unit. We shall see...

 

[Randy Holmes-Farley]

I had high silicate levels as well with my Triton results. Just added a SilicaBuster DI membrane to my RODI unit. We shall see...

Did you try measuring silicate in the DI water?

 

[Volcmreefer]

I have a Salifert silica test kit on the way. Using Instant Ocean salt. I am going to measure the water, saltwater, and tank when it arrives. Needed to replace my DI cartridge anyways, so I replaced with a spectrapure MaxCapDI cartridge and installed a single housing after with a SilicaBuster DI cartridge. Hopefully this will help.

 

[Volcmreefer]

I am running a DSB. Not sure if that is a factor in the results or not.

 

[Volcmreefer]

I have a Salifert kit on the way. Replaced my DI housing with a MaxCapDI cartridge and installed a new housing and cartridge downstream with a SilicaBuster. Hoping it will help. I use Instant Ocean salt.

 

[Eric Morissette]

Following

 

[Volcmreefer]

I am receiving the Salifert Silica test kit today. Will test all of my water tonight and post results.

 

[BigJim]

I had a similar reading from my ATI ICP test and always have a small amount of diatoms on my sand bed. ATI also tests RODI water and mine had a high amount of silicon. I bought the Anion DI resin from BRS to run in a second DI canister. I also purchased the Salifert Silicate test kit and it show 0 silicates. I guess I will never know for sure if they are being removed but hopefully the diatoms will go away,

 

[Volcmreefer]

Hope so BigJim! Trying to pinpoint the source is going to be tough. Hoping it is an easy fix.

 

[Derek Clifford]

I've got a bit of a head-scratcher in terms of how I proceed with a slight silicate problem in my tank.

I have a very similar situation, for many months.
approx 400 silicate on Triton. salifert 0. seachem 0.
I tried rowaphos and silicat-ex at different times. But GFO kept my phosphate at 0 and caused me Dinoflagalette problems.

I got an triton ICP on my DI water at one point and it measured 1400. I resolved that by installing a booster pump on RODI unit.

Silicates still about 400 after several months. But I had to stop the GFO to get phosphates up and I have recently started dosing phosphates.

I will be sending another ICP soon, so I will be interested where silicates are at.