Spot Free TDS Questions: Need schooling

[slash007]

Pat, good advice, I'll do that.

Mep, I do have 2 autos, so it does get used quite a bit. Being over a year now, it must be the chlorine or the membranes. I have never changed either, but guess the membranes are not too hard to change. What about the chlorine? Something I could do myself pretty easily? What about the best place to buy it, and how to know how much I need? Thanks.

 

[MEP001]

Chlorine will ruin the membranes, so it's not exactly one or the other - you aren't filtering chlorine to improve RO quality.

The membranes aren't usually hard to change, although I've worked on some where it's very difficult to get them out.

Assuming you have a chlorine prefilter that is basically a small softener tank, you would need to dump the media out and refill it. It needs to be 2/3 to 3/4 filled, so you'd get the volume of the cylinder to determine how much. Can't say best place to buy, if you can find it locally for a good price and not have to pay shipping that would be great, or try discountwatersofteners.com.

 

[slash007]

You're right, I forgot how it works. At least I'll known if it was the chlorine that killed the membrane. I bought a softener and carbon tank for my other wash from discountwatersofteners.com I'll check local first though for the media. To test the TDS, I have just been testing it from the SFR tank. Is there a better way? I just dip the cap of the tester in there then put the cap on the tester to get the result. Should I be dipping the tester in the tank? Thanks.

I also wanted to ask about the different carbon types. I see many types listed. Any particular type better than the others for the car wash?

 

[2Biz]

When making sfr, catch some with a clean plastic cup as it enters the tank. Take a reading from that and compare to what's in the tank. It will tell you 2 things, filter quality and tank contamination.

 

[slash007]

When making sfr, catch some with a clean plastic cup as it enters the tank. Take a reading from that and compare to what's in the tank. It will tell you 2 things, filter quality and tank contamination.

Great idea. It's amazing the simple things that you don't even think of. That's why I love this place

 

[MEP001]

I usually test it in a bay, mainly because it's the easiest place to get a sample. I test it straight from the unit only if the reading from the bay is high.

 

[slash007]

For testing the chlorine, will a simple pool/spa test strip work, or do I need to use the powder method that you swirl in a container? Also, I have two membranes on my RO system. They are both 4x40 and should produce 3200GPD. Since I am only using this unit on a 6 bay self serve and have a large holding tank, would it be fine if I bypassed one of the membranes and just used 1? Or is there any benefit to using both other than the larger production capability? If using both means they would last double, I don't mind keeping both.

 

[MEP001]

The pool/spa testers work, but they aren't usually sensitive enough to detect a trace of chlorine, which is why I test the RO reject for chlorine. It will be concentrated there.

You can bypass one membrane, but I wouldn't do that until it's time to replace them. The one bypassed will go bad not being used, so might as well get all the life out of it that you can. You will have to adjust or re-route part of the pump flow since it's sized for two membranes.

 

[slash007]

The pool/spa testers work, but they aren't usually sensitive enough to detect a trace of chlorine, which is why I test the RO reject for chlorine. It will be concentrated there.

You can bypass one membrane, but I wouldn't do that until it's time to replace them. The one bypassed will go bad not being used, so might as well get all the life out of it that you can. You will have to adjust or re-route part of the pump flow since it's sized for two membranes.

I am replacing the filthy membranes on a used stand, so figured this might be the best time to by pass one membrane if I don't need both. I was just going to couple the lines together from the removed membrane to the one I keep. Will that not work? What other adjustments would I have to make? I don't think I can adjust anything other than production/reject.

 

[pgrzes]

Slash if you have 2 autos plus your self serve running spot free are you sure you will be able to supply enough SF water to everything at peak demands with only one membrane? I have trouble keeping up with just my 1 auto in the winter time making spot free water. When the temps drop even with a cold water membrane I cant make enough SF water to keep up.

 

[slash007]

Slash if you have 2 autos plus your self serve running spot free are you sure you will be able to supply enough SF water to everything at peak demands with only one membrane? I have trouble keeping up with just my 1 auto in the winter time making spot free water. When the temps drop even with a cold water membrane I cant make enough SF water to keep up.

I have 2 membranes at that wash, I am putting in SF at a wash that only has six SS bays and no autos. It never had SF before, but my pump stand that I just put in has it, so I am trying to activate it.

 

[I.B. Washincars]

Slash's wash is a 6 bay SS, no autos. One membrane will be more than enough. I ran a very busy 4 bay on a system with just one 2" membrane and a 300 gallon tank.

 

[MEP001]

The easiest way to modify it would be to put a regulator or valve on the pump outlet to return some flow back to the pump inlet. If you don't do this, you'll either over-pressurize the membranes to get the flow right or you'll have to dump too much down the drain to keep the pressure down. I'd suggest replumbing the whole thing while you're making changes so that you can run the unit at 1:1 product/reject, which will save you a lot of water and seems to increase production.

 

[slash007]

I measured the reject water for total and free chlorine and both were 0. I checked the TDS in the tank again and it was 26. Looks like I'll need to replace those membranes soon.

 

[2Biz]

Did you see what the water tested as it enters the tank?

 

[slash007]

Did you see what the water tested as it enters the tank?

Yes, it was the same as the tank. 26ppm. To be fair, it was hard to get a sample as it came out of the outlet, so maybe it had tank water in it as well. I'll try again with the tank lever lower to get a perfect sample.

 

[MEP001]

26 should be acceptable. The TDS doesn't always get higher over time, in fact sometimes it can drop. Does it still dry without spots?

 

[2Biz]

Yes, it was the same as the tank. 26ppm. To be fair, it was hard to get a sample as it came out of the outlet, so maybe it had tank water in it as well. I'll try again with the tank lever lower to get a perfect sample.

So I thought most SFR tanks were the same! Mine has a big lid on top...It has a float switch that floats on top of the water. The SFR water comes in the tank at the top just inches away from the lid through a bulkhead fitting. I can manually activate a cycle and catch the water as it enters the tank. You can't do that? Water level is down about a foot from where it comes in the top of the tank...

 

[slash007]

So I thought most SFR tanks were the same! Mine has a big lid on top...It has a float switch that floats on top of the water. The SFR water comes in the tank at the top just inches away from the lid through a bulkhead fitting. I can manually activate a cycle and catch the water as it enters the tank. You can't do that? Water level is down about a foot from where it comes in the top of the tank...

That's exactly what I did, but my water lever is only about an inch if not less from where it comes in. I slid a cup under the fitting and manually activated it using the float, but with so little room, maybe I got tank water in the cup as I removed it. Hope that explains it....