RO question...TDS is 16 out the tap...

[digitalintrigue]

Hi all, first post here, have had reef tanks off and on for 25+ years...two tanks currently but no corals, just a FOWLR, but will soon start acquiring frags to populate a 10 gallon.

Our new house uses rainwater collection, and the reading on my TDS meter out the faucet is 16.

The house water system has a sediment filter, carbon filter, and UV.

Is it even worth using an RO to get TDS to zero, or just use the water as-is?

Thanks in advance!

 

[Rmckoy]

Although there is only 16 total dissolved solids . Being precipitated water held in storage containers we can only hope it’s water and no pollutants taken from the atmosphere .
with uv , carbon and it should be ok …

16 isn’t that bad . But it’s not great either .

 

[Tathamet]

You might be able to get away with it but you don’t really know what that 16 tds actually is.

I’d still think using rodi is the way to go though. And with that low of a tds your membranes, cartridges, and di resin should last a lot longer than normal which is nice.

 

[digitalintrigue]

This is true, there wouldn't be much waste water coming out of the RO...

16 is super-low compared to what I'm used to at my old house (200ish)

 

[Randy Holmes-Farley Verified Community Expert]

You might consider di only, but I would not risk raw tap water without a detailed test on it, even if it is 10 ppm tds.

 

[JoshH]

You might consider di only, but I would not risk raw tap water without a detailed test on it, even if it is 10 ppm tds.

This was my thoughts as well, Triple stage DI should still last a long time with zero waste and provide excellent water.

Any tank troubles and you will always be wondering if it's your water or something else.

 

[theMeat]

At 16 tds you’d go through a lot of di resin. Agreed, test water and see what the tds is, might be fine as is

 

[alann]

I agree with the others about using di only, my water is less than 10 ppm tds out of the tap but I still put it through di, but you can also test the water to see what's in the tds.

 

[TangerineSpeedo]

Well 15 TDS makes sense. That is what I get after my sediment and carbon filters.
Rain water collection... You dang hippie!
I would still run a full system regardless because at least you know for sure you are good on your tank water. Just in case you get lazy on the house filters. The good news is, your house water will be an excellent prefilter and you will have to change filters on your RODI less. Probably get away with just a 4 stage.

 

[digitalintrigue]

Hah! We love our rainwater! We had two full days of showers last week and our tanks are completely full for the first time. We have well water for backup, but it's SUPER hard.

I've decided there is no reason not to do full RO/DI and get it down to zero.

Thanks everyone for your comments!

 

[RaymondL]

You might consider di only, but I would not risk raw tap water without a detailed test on it, even if it is 10 ppm tds.

Randy: I came across the article you wrote about TDS - thank you! In your opinion what is the maximum allowable TDS range before negative impact to the reef tank might occur. Ie. 1-5ppm ok, >10ppm not good, etc.

Thanks