DI necessary? Help with tap water parameters

[Royal_pudding]

Hi all.
So I have been looking at RO units due to diatoms in my reef and freshwater tank. I suspect it might be something in the tap water i have been using.
I found some data on the chemical analysis of said water, only it is 6 years old.
I have attached an absolutely horrendous image that is snipped from the report using my phone. But it is readable.
I am only 4 months into reefing and making sense of this seems daunting. Heres to hoping someone can give me a short answer to a simple question

Is this ****** water?

 

[BetterJake]

Honestly the best way to find the answer is to just buy a TDS meter and test it. If your tap water TDS is above 0, which I'm almost 100% certain it is, it's to time to buy an RODI unit or start getting water from your LFS

TDS Meter

 

[BetterJake]

Honestly the best way to find the answer is to just buy a TDS meter and test it. If your tap water TDS is above 0, which I'm almost 100% certain it is, it's to time to buy an RODI unit or start getting water from your LFS

TDS Meter

The good thing is that once you start using 0 TDS water the diatoms should just die off eventually since they will run out of silicia to consume.

 

[Royal_pudding]

The good thing is that once you start using 0 TDS water the diatoms should just die off eventually since they will run out of silicia to consume.

That is true. It also rules out the water as a cause for algae.
Thank you

 

[Spare time]

You need a DI to remove silica

 

[BetterJake]

That is true. It also rules out the water as a cause for algae.
Thank you

I mean at this point if you are using tap water that's going to cause diatoms and other issues as well. RODI for water isnt a nice to have in this hobby, it's a must have. It's either that or buying water from your local fish store.

 

[Jekyl]

Agree with above. Also I don't think you want to use RODI for freshwater

 

[BetterJake]

Agree with above. Also I don't think you want to use RODI for freshwater

I'm still new, but I'm pretty sure top off freshwater should be RODI water as well, otherwise you run into the same issues discussed

 

[Jekyl]

I'm still new, but I'm pretty sure top off freshwater should be RODI water as well, otherwise you run into the same issues discussed

I meant as in a freshwater tank, not salt since you mentioned both.

 

[BetterJake]

I meant as in a freshwater tank, not salt since you mentioned both.

Ah yes, for just a freshwater tank should be fine

 

[sghera64]

I don’t use DI any more. I only use my RO. I just jade my RO water checked by ATI labs (mass spec). It is really clean except 117 micro grams per Liter if silicon. I don’t have diatoms and never in 20 years have I in this 200 gallon system. I do run all my top-off through pH14 kalkwasser reactor but not the water changes. The RO water tends to come out between 1 and 3 PPM TDS.

 

[Randy Holmes-Farley Verified Community Expert]

FWIW, if you have an ongoing diatom problem in an established tank, silicate in the RO/DI effluent is the most likely source of silicate for the diatoms, and the DI is important for removing it. Maybe 2 DI in series. Diatoms cannot live without a silicate source.