Help with high silica levels

markster33139

New member
So I just got my Triton readings back, and I guess I know why my tank is covered in diatoms. The usual suspects are PO4 0.025, Ca 484, Mg 1455, Alk 9.2, but Si 605 ug/l. On 8/22/2016 Aqua Medic had also tested Si at 3.2 mg/l. In trying to combat this unsightly mess I have replaced all of the stages of my 5 stage BRS RODI even though I was getting 0 TDS. I have removed most of my already extremely shallow sand bed. I recently rebooted the tank about 4 months ago to install a starboard bottom, and I only added 40 lbs of Carib Sea Special Grade, and now I probably have 20 lbs left. Skimmer is an ATB 840 V2, and it is working very well, so I am at a loss. Does anyone think it could possibly be my sand, can liverock leach silicates? I do run GFO, and carbon dose with vinegar, but the GFO doesn't seem to be doing much for the silicates. Should I remove the rest of the sand? Thank for any assistance.
 

bertoni

Premium Member
Live rock shouldn't leach silicate. 0.6 ppm silicon (which I think is what they are testing) is below natural sea levels (5 ppm):

http://reefkeeping.com/issues/2005-11/rhf/index.php

I wouldn't worry all that much about silicate. The diatoms require phosphorus to grow, so I'd work on that. Measurable phosphate implies there's plenty of that nutrient to fuel growth.
 

jason2459

Premium Member
Once your DI gets near exhaustion silica will start working its way through. DI isn't very good at binding it. And your TDS will still show 0.

Here's results of different stages of DI exhaustion showing Si levels at even 75% color change. TDS was 0 the entire time.

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7a8eafd2c70723b3b1f31988e94e7016.jpg
 

markster33139

New member
Thank you that's makes a lot of sense actually which is why I changed all the components in my RODI. I think though that I have a lot of silica in my tank and hopefully many repeated water changes can get the levels down as GFO is not really doing it.

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jason2459

Premium Member
Keep the GFO going as it will help. Not sure if I missed it but are you running the GFO in a reactor? Are you running it with a reactor with the Carbon?

In a reactor by itself and freely tumbling well would be the most effective. I do know some(usually "old timers") have added a small bit of carbon in it to help keep it from clumping.
 

Big E

Premium Member
I think there are a few RO setups that use some GFO mix in one of the cylinders.

I believe that's what Spectrapure calls it's Silica buster Resin.

I would think this would help at a possible source in your case. I don't know for sure on the amount or results, but you could mix in some GFO on your own and do some testing.
 

markster33139

New member
Good idea and funny you mention that. I am currently adding that same cartridge called the silicate buster as stage 6 to my RODI

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neiltus

New member
Going through the same thing right now...my DI canister was about at 75% and had a diatom outbreak, I replaced the DI and put another DI stage after, hopefully that helps.

Also ordered a silica buster to try at some point before my normal DI if it continues being a problem.

Appreciate the chart Jason.
 
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