Silicon / Silicates in RODI water

[wazupjames]

Keep getting Silicon readings in my ICP tests for RODI water. Using a 4 Stage KleanWater Advanced RODI system with Booster Pump. Always use Color Changing DI Resign and change it out when 1/3 has changed color. TDS always reads 0. Does anyone have any ideas as to what is causing the silicates to get through or what I can add to the unit to remove the silicates?

 

[Fish Think Pink]

Keep getting Silicon readings in my ICP tests for RODI water. Using a 4 Stage KleanWater Advanced RODI system with Booster Pump. Always use Color Changing DI Resign and change it out when 1/3 has changed color. TDS always reads 0. Does anyone have any ideas as to what is causing the silicates to get through or what I can add to the unit to remove the silicates?

confused... do you literally at same time:
- spend money on ICP test for RODI (only!) water
----- comes back saying silica/silicon present in water
- TDS reads 0

Would think silica is dissolved solid, so your meter saying zero total dissolved solids AND ICP test saying zero doesn't make sense... unless your TDS meter is broken... perhaps get second opinion- I'm DFW TX but Vegas NV has active reefer community so LFS or someone local-to-you should be able to help you out

Change your RODI filters, and when you do, wipe down everything with microfiber (no lint) cloth while it is apart, so you can be sure it is clean when you put it back together. I have a different RODI manufacturer (in build thread) and I can't go by color alone but by TDS... and my TDS meter works but I'm waiting until reach 6 before I change filters...

 

[Randy Holmes-Farley Verified Community Expert]

Keep getting Silicon readings in my ICP tests for RODI water. Using a 4 Stage KleanWater Advanced RODI system with Booster Pump. Always use Color Changing DI Resign and change it out when 1/3 has changed color. TDS always reads 0. Does anyone have any ideas as to what is causing the silicates to get through or what I can add to the unit to remove the silicates?

Silicate is among the hardest ions to remove by RO/DI, but unless you have problematic levels of diatoms, it is no concern. i regularly dosed silicate to my tank.

If you do have problems with diatoms, adding another DI in series can help.

 

[Cjeippert]

Silicate is among the hardest ions to remove by RO/DI, but unless you have problematic levels of diatoms, it is no concern. i regularly dosed silicate to my tank.

If you do have problems with diatoms, adding another DI in series can help.

I find running a stage with just anion di resin works to remove high levels of silica or using the silicabister from spectrapure helps. If I remember correctly silicate is a -4 anion and can easily be re released in water once di resin is used up. So if I waited until my tds said 1, then I know a bunch of stuff probably made it into my rodi water. I have heard of some people liking some silica because it produces some diatoms which out compete cyano.

 

[Randy Holmes-Farley Verified Community Expert]

I find running a stage with just anion di resin works to remove high levels of silica or using the silicabister from spectrapure helps. If I remember correctly silicate is a -4 anion and can easily be re released in water once di resin is used up. So if I waited until my tds said 1, then I know a bunch of stuff probably made it into my rodi water. I have heard of some people liking some silica because it produces some diatoms which out compete cyano.

That all makes sense. Yes, silicate can get through to some extent and is among the first ions released from a DI when it begins to deplete because it readily forms uncharged silicic acid that will get away.

In general, folks should not be concerned with removing all silicate unless diatoms are at problematic levels.

 

[bumpyj38]

That all makes sense. Yes, silicate can get through to some extent and is among the first ions released from a DI when it begins to deplete because it readily forms uncharged silicic acid that will get away.

In general, folks should not be concerned with removing all silicate unless diatoms are at problematic levels.

That all makes sense. Yes, silicate can get through to some extent and is among the first ions released from a DI when it begins to deplete because it readily forms uncharged silicic acid that will get away.

In general, folks should not be concerned with removing all silicate unless diatoms are at problematic levels.

I have a 7 stage RODI system from BRS. It has 3 stage DI (cation, anion, and mixed bed). I have always had 0 tds and not let it even get close to needing to be changed out, yet I have a relentless problem of Chrysophytes and diatoms. One that must be getting refueled by my auto top off. So, is there a possibility that it gets through even when registering 0 TDS? By the way the 7 stage has 2 separate TDS meters that come after the anion and mixed bed. Both of them read zero so I wouldn’t believe that my TDS meter is wrong.

 

[Randy Holmes-Farley Verified Community Expert]

Yes, it is possible for enough to contribute to silicate but not reach 1 ppm TDS.

You might bet a kit or an ICP test on the RO/DI to see if it is the source.

Do you know if your water company adds silicate?

 

[Cjeippert]

I have a 7 stage RODI system from BRS. It has 3 stage DI (cation, anion, and mixed bed). I have always had 0 tds and not let it even get close to needing to be changed out, yet I have a relentless problem of Chrysophytes and diatoms. One that must be getting refueled by my auto top off. So, is there a possibility that it gets through even when registering 0 TDS? By the way the 7 stage has 2 separate TDS meters that come after the anion and mixed bed. Both of them read zero so I wouldn’t believe that my TDS meter is wrong.

My silicate comes from artificial dry rock and the ceramic bricks. This goes away. Especially with water changes and gfo and time. And trochus and turbo snails mow the grass nightly… tangs too

 

[bumpyj38]

Yes, it is possible for enough to contribute to silicate but not reach 1 ppm TDS.

You might bet a kit or an ICP test on the RO/DI to see if it is the source.

Do you know if your water company adds silicate?

I have well water with 550 TDS from source. I run the 7 stage and my anion exhaust extremely fast (about 100 gallons. Maybe a little less).

I’ve heard bad things about Salifert Silicate test. I was thinking of possibly Hanna Low range checker if anyone has anything good to say about it.
So, no matter the test kit I get, a good water supply should be 0 ppm Silica? What is an acceptable range for a reef tank?

 

[Cjeippert]

My silicate comes from artificial dry rock and the ceramic bricks. This goes away. Especially with water changes and gfo and time. And trochus and turbo snails mow the grass nightly… tangs too

Silicon can get through with 0 tds. I use both brs and spectrapure locally in AZ. I tend to like the max cap and silicabusters a bit more.

 

[bumpyj38]

My silicate comes from artificial dry rock and the ceramic bricks. This goes away. Especially with water changes and gfo and time. And trochus and turbo snails mow the grass nightly… tangs too

This could be. I upgraded my tank using all the live rock from my previous tank and some new dry rock from Addictive Reef Keeping in my 220 gallon system. Interesting point. So if my RODI tests zero then I could assume it would be coming from the rocks? If so the silicates will eventually be used up and should be lowering in number as I test the reef daily/weekly correct?

 

[ReefKeeperElite]

Silicate is among the hardest ions to remove by RO/DI, but unless you have problematic levels of diatoms, it is no concern. i regularly dosed silicate to my tank.

If you do have problems with diatoms, adding another DI in series can help.

Agree with this. My ICP analysis came back with silicates of 340 ppm. I use the silicabuster membrane along with sediment, 1 micron and 5 micron carbon blocks, cation, anion, and mixed bed DI filters. I have 4 8x8x4 MarinePure blocks in my sump, which I'm sure is the reason for the high silicates. Despite the high silicates, I have no diatom issues, and things are doing fine. So I see no reason to worry about my high silicates. Open to thoughts though if something else beside diatoms may result from high silicates.

 

[131696]

There's a Silicate filter you can put in RoDI system that will help with that

Silica Buster DI Filter Cartridge 10" - Spectrapure​

 

[bumpyj38]

Agree with this. My ICP analysis came back with silicates of 340 ppm. I use the silicabuster membrane along with sediment, 1 micron and 5 micron carbon blocks, cation, anion, and mixed bed DI filters. I have 4 8x8x4 MarinePure blocks in my sump, which I'm sure is the reason for the high silicates. Despite the high silicates, I have no diatom issues, and things are doing fine. So I see no reason to worry about my high silicates. Open to thoughts though if something else beside diatoms may result from high silicates.

Chrysophytes are also fed by silicates. They have the appearance of Dinos only they are not toxic like some strains of Dinos. They look horrible though. I’m currently trying to solve my issue (suspect that it’s silicates as stated above) in hopes that they will die off.

 

[AquamanE]

confused... do you literally at same time:
- spend money on ICP test for RODI (only!) water
----- comes back saying silica/silicon present in water
- TDS reads 0

Would think silica is dissolved solid, so your meter saying zero total dissolved solids AND ICP test saying zero doesn't make sense... unless your TDS meter is broken... perhaps get second opinion- I'm DFW TX but Vegas NV has active reefer community so LFS or someone local-to-you should be able to help you out

ATI ICP tests not only test Saltwater, but also includes a vial for RO/DI water. Same cost AND includes postage To return back to them.