How do you know when its time to replace your RO filter?

[AZDesertRat]

Chris see my post above yours. No need for and expensive valve. A tee placed between the RO and the DI with a short piece of 1/4" tubing, an inexpensive 1/4" ball valve and some more tubing long enough to reach the drain does the trick. An added advantage of the DI bypass valve is it gives you an easy accessible place to draw RO only water to test the TDS with your handheld TDS meter and to fill jugs or pitchers with RO drinking and cooking water or for dog and cat water or water for freshwater tanks.

 

[Randy Holmes-Farley Verified Community Expert]

So it's not good to make small batches right?

Correct. It uses the DI resins faster. But the water produced is just as good.

 

[SROPE]

You need the three way valve to test the tds out of the membrane right? I found the one BRS has. It's pricey but I think that's my only choice. Because no one carries them locally.

Yes Chris but AZ just gave us a lesser expensive option. Would take up more room but can be bought at Lowe's or HD.

 

[chris124]

It does not need to be an expensive 3 way valve to flush the TDS creep out. A 1/4" tee and a ball valve accomplishes the same thing at less than half the cost of a 3 way valve.

Also lets make sure no one is confusing a "flush kit" which installs in the waste line and does little besides giving you a warm fuzzy feeling with DI bypass valve which installs with a tee and ball valve or the more expensive 3 way valve in the RO treated water line and has value.

So I don't need a valve to stop water from going through the DI right? Just the ball valve on the end of the tubing.

 

[SROPE]

Chris see my post above yours. No need for and expensive valve. A tee placed between the RO and the DI with a short piece of 1/4" tubing, an inexpensive 1/4" ball valve and some more tubing long enough to reach the drain does the trick. An added advantage of the DI bypass valve is it gives you an easy accessible place to draw RO only water to test the TDS with your handheld TDS meter and to fill jugs or pitchers with RO drinking and cooking water or for dog and cat water or water for freshwater tanks.

I like the idea but wouldn't the high tds water still be run thru the DI at the same time?

 

[chris124]

I like the idea but wouldn't the high tds water still be run thru the DI at the same time?

That's what I was wondering.

 

[AZDesertRat]

The water will take the path of least resistance. We are talking a few ounces per minute not a solid pressurized stream. As long as the tee and valve are running downhill that's where the water is going to go

 

[SROPE]

Now I want a 3-way valve again.

 

[AZDesertRat]

I have used the tee and ball valve method for about 15 years now.

 

[chris124]

I have used the tee and ball valve method for about 15 years now.

Well you just saved me some money thanks. Just one more question. When I make water I need to send the first few minutes of water through the DI bypass until the tds gos down right?

 

[AZDesertRat]

Correct. You are flushing out the 4 or 5 ounces that has been pulled from the waste side of the membrane to the treated side during inactivity. Remember, RO water has been stripped of 90-98+% of its contaminants or ions so is aggressively trying to get back to its natural "dirty" state and pulls TDS through the membrane until it equalizes. Since the TDS on the waste side is 25% or so higher than the tap was to begin with it can be quite significant and exhaust resin much quicker.

 

[chris124]

Correct. You are flushing out the 4 or 5 ounces that has been pulled from the waste side of the membrane to the treated side during inactivity. Remember, RO water has been stripped of 90-98+% of its contaminants or ions so is aggressively trying to get back to its natural "dirty" state and pulls TDS through the membrane until it equalizes. Since the TDS on the waste side is 25% or so higher than the tap was to begin with it can be quite significant and exhaust resin much quicker.

My in line tds meter connects to a tee so if disconnect that then all I would need is the ball valve.

 

[AZDesertRat]

That would work. I don't use my inlines so could substitute a short piece of tubing and a valve in place of the probes and have a place to collect TDS readings at the important places with my handheld.

 

[chris124]

That would work. I don't use my inlines so could substitute a short piece of tubing and a valve in place of the probes and have a place to collect TDS readings at the important places with my handheld.

Thanks.