Cryptic problem: RO membranes clog up. Please help

[rajdude]

Easy way to get water but not a very good long term solution especially with your hard water. I worked for an appliance store when I was in high school a number of times I would get sent out to look at someones ice maker and my repair would be shutting off the piercing valve and turning it back on to clean the build up off the pierce. I do not think that is your problem since I do not remember a low pressure when making RO for you.

I agree with you there Pressure may not be a problem here.

However, my apprehension about the needle valve reducing flow is coming from an observation we had while troubleshooting this system:

I connected a tube straight from the needle valve and let it drain in a bucket. I took a video of the flow of water coming out from it. Sent it to Joe from Pure Water Products (I bought my RODI setup from him).
He then sent me a video of the same thing in his office.

The water flow shooting out from my tubing was significantly slower than his water flow.
Interestingly, water pressure on his side and my home measures very closely.


Since the flow is not good, I suspect it may not do a good job while flushing the membrane.

Hence the fancy sharkbite thingy ;-) But lets see if that really makes any difference!

 

[rajdude]

Easy way to get water but not a very good long term solution especially with your hard water. I worked for an appliance store when I was in high school a number of times I would get sent out to look at someones ice maker and my repair would be shutting off the piercing valve and turning it back on to clean the build up off the pierce. I do not think that is your problem since I do not remember a low pressure when making RO for you.

and oh yes....I also tried the same thing...shutting off the piercing valve and rotating it back on. That did not improve the flow.

I guess that the hole created by the piercing needle is too tiny to allow good flow of water. It seems to act like the flow restrictors in our showers (and these RODI system drains).

Hopefully that shut off valve has a bigger orifice in comparison.

 

[rajdude]

Surgery and analysis:

ok so I cut the fouled membrane open and observed this:

• White gritty stuff is visible and can be felt on the membrane.
• Grit is more visible in the lower half of the membrane, away from the inlet, which is shown to the left in the photo below.
• If the rub the grit with my finger, it turns grayish (this is weird).
• Dropping a few drops of muriatic acid on this gritty stuff causes fizzing. That means it could be calcium deposits coming from the hardness in my water.

I called Russ from Buckeye Hydro and talked to him about this. He says he sure sounds like hard water deposits on the membrane foul it. There are two possible solutions he proposed:

1. Try 4:1 waste: product water ratio, or
2. Add a water softener

Solution #1
I could try #1 solution, but am pretty worried about all the waste water going down the drain, along with the cost of it on my water bill, which is already pretty high, in my opinion.


Solution #2
Another "solution" is to reduce my RO water consumption. The Discus tank does not "really" need RO water. Two options:

• Stop it: I could stop using RO for the aquarium and have it only for drinking water.
• Blend it: I could run 50% filtered water + RO water in there also. I hear some Discus fish keepers do this.

But gotta install that sharkbite first. More to come...

 

[rajdude]

ok I did a little bit of research and math and it seems to me that my apprehension about using too much water may not be really true.

If I google average water usage, I get various answers, but usually it is around 75 gallons per person per day.
(9000 gallons per month for a family of 4)

How We Use Water | US EPA

Less water going down the drain means more water available in the lakes, rivers and streams that we use for recreation and wildlife uses to survive.

www.epa.gov

https://www.neefusa.org/weather-and-climate/weather/home-water-use-united-states#Virginia

So, that is pretty much what my household's last quarter bill was, at 27000 gallons
That is with the RO filter working.

Hmmm. Interesting.

So I went back and did some math related to the RO water cost, at the new, proposed 4:1 (waste to product) water ratio.

So yeah, 50 bucks per month sure will pinch. I guess if I blend it 50:50, it comes down to a little bit more pocket friendly number.

PS: I usually change water every other day, but looking at the Nitrate levels, I really need to change every day.

 

[Malcontent]

PS: I usually change water every other day, but looking at the Nitrate levels, I really need to change every day.

What are your nitrate levels?

 

[sfin52]

Surgery and analysis:

ok so I cut the fouled membrane open and observed this:

• White gritty stuff is visible and can be felt on the membrane.
• Grit is more visible in the lower half of the membrane, away from the inlet, which is shown to the left in the photo below.
• If the rub the grit with my finger, it turns grayish (this is weird).
• Dropping a few drops of muriatic acid on this gritty stuff causes fizzing. That means it could be calcium deposits coming from the hardness in my water.

I called Russ from Buckeye Hydro and talked to him about this. He says he sure sounds like hard water deposits on the membrane foul it. There are two possible solutions he proposed:

1. Try 4:1 waste: product water ratio, or
2. Add a water softener

Solution #1
I could try #1 solution, but am pretty worried about all the waste water going down the drain, along with the cost of it on my water bill, which is already pretty high, in my opinion.


Solution #2
Another "solution" is to reduce my RO water consumption. The Discus tank does not "really" need RO water. Two options:

• Stop it: I could stop using RO for the aquarium and have it only for drinking water.
• Blend it: I could run 50% filtered water + RO water in there also. I hear some Discus fish keepers do this.

But gotta install that sharkbite first. More to come...

I would add a water softener. This would have multiple bennifits in the home. Extend life on all water using devices and extend the life of your ro system. Just my thoughts. Those deposits clog everything.

 

[rajdude]

What are your nitrate levels?

I should test again, but a month back it was nearly 100! That was with water changes every other day and sometimes slacking too (rare, but did happen). I have cleaned up my act since then.

When I was doing daily water changes, it hovered around 30-40. Gotta go back to that number.

PS: This is a freshwater planted tank with Discus fish.

 

[Buckeye Hydro]

And on the water softener part I can't remember but I want to say that it will use up resin quicker because the salt gets past the membrane, but I could be wrong on that but for some reason I remember there being a different aspect when going after a water softener.

This is not correct.

 

[Buckeye Hydro]

ok now I get it what you are saying. I may be fine with that. Let it run slowly, as long as the waste water is not too high.

What restrictor flow rate would you recommend?

Right now my permeate flow is measuring 90ml/min
Looking at BRS' website, the slowest I get get is 200 ml/min

Reverse Osmosis Flow Restrictor

Flow restrictors are essential to a properly functioning RO system. Be sure to have the appropriate flow restrictor for the membrane you have. If you decide to change your membrane to a higher or lower GPD membrane, you must also replace the flow restrictor to correspond with the membrane. All...

www.bulkreefsupply.com

I can live with the above but the restrictors I like don't come lower than 400 ml/min

Reverse Osmosis Membrane Flush Valve

The Membrane Flush/Flow restrictor valve is an all in one flow restrictor equipped with a flush valve for easy worry free use. Keeping the flush and flow restrictor in a single package keeps fitting count down which means less chance for possible leaks or failures down the line. 550 mL/min for...

www.bulkreefsupply.com

Raj - we have more flow restrictors at different flows if you still are looking for them.

 

[Buckeye Hydro]

I didn't realize OP was running 1:1.

So OP does have HARD WATER, and his RODI was setup in a 1:1 configuration, with no pre-treatment of his hard water. I'm pretty sure running a system 1:1 with hard water is not recommended because your membrane will scale up quickly in this configuration. Water hardness will deposit as scale inside the membrane. The membrane needs MORE water to flush out the scale, restricting the system down to 1:1 makes the problem worse. anybody with HARD water, without a water softener should not be running 1:1 from what I understand. I think if OP reconfigured the system to be 2.5:1 or so, with more water running through, not less, the membranes might last longer.

I didn't realize OP was running 1:1.

So OP does have HARD WATER, and his RODI was setup in a 1:1 configuration, with no pre-treatment of his hard water. I'm pretty sure running a system 1:1 with hard water is not recommended because your membrane will scale up quickly in this configuration. Water hardness will deposit as scale inside the membrane. The membrane needs MORE water to flush out the scale, restricting the system down to 1:1 makes the problem worse. anybody with HARD water, without a water softener should not be running 1:1 from what I understand.

You are right on the money here.

 

[thatmanMIKEson]

This is not correct.

Ok, was there anything different when using a water softener, or did my lizard brain make that up?

 

[thatmanMIKEson]

This is not correct.

Ahh sorry, this is what I may have been thinking of, I'll quote the man.

That's not the reason.

A water softener does NOT decrease the ppm TDS of the water. It actually increases it a little bit as it swaps in two sodium ions for one calcium or one magnesium.

What it does do is greatly decrease the tendency for calcium and magnesium carbonate to precipitate onto or into the RO membrane, clogging it. Thus, the softener prolongs the membrane lifetime.

The trade off is it may deplete the DI a little faster since sodium gets through a RO membrane a little more readily than does calcium or magnesium.

 

[thatmanMIKEson]

This is not correct.

that's almost exactly what I said, I knew I remembered reading that somewhere, what do you think?

 

[thatmanMIKEson]

This is not correct.

Post in thread 'RO/DI with water softener questions?' https://www.reef2reef.com/threads/ro-di-with-water-softener-questions.856715/post-9330472


Here's the thread where he mentions that, it sounds right to me, what do you think is it correct?

 

[Buckeye Hydro]

Randy is correct, but practically speaking it is a non issue.

For the commercial RO systems (w/ ~ 1:1 ratio , or 50% recovery) we install, where membranes can get pretty pricey, a water softener is a routine pretreatment. The money saved on membrane replacements and water far exceeds any very minor increase in TDS. Sodium is removed well by a membrane.

This hobby is challenging in that users want
100% recovery,
100% rejection,
at low pressures,
with no feedwater lab testing,
with no pretreatment,
at a very low cost.

 

[thatmanMIKEson]

Randy is correct, but practically speaking it is a non issue.

Sweet then by default I'm correct

And of course it's not an issue but it is happening...and correct

Thanks 4 the information

 

[rajdude]

I should test again, but a month back it was nearly 100! That was with water changes every other day and sometimes slacking too (rare, but did happen). I have cleaned up my act since then.

When I was doing daily water changes, it hovered around 30-40. Gotta go back to that number.

PS: This is a freshwater planted tank with Discus fish.

I tested the Nitrate levels yesterday. Came to 40. Not too bad.

 

[rajdude]

Good morning all! I got a bunch of stuff done yesterday night.
Time for updates:

Check your water flow (in addition to the pressure)!
So I installed the sharkbite tee and shut-off valve combo. Here is what it looks like:



I compared the water flow between the saddle valve and this new tee based shut-off valve. WOW
The difference is night and day!

Just like I posted earlier, the measured pressure is exactly the same...around 70 PSI. However the flow of water shooting out is much, much faster from the shut-off valve. Why? Clearly it is the orifice size difference.

Why does it matter to us?
Well, when we flush the membrane, it is the flow of water which will flush away the sediments and impurities from the RO membrane. In my case, the flow was too low. So even if I flushed, the membrane was probably not getting cleaned/flushed.

Showing pressure when the outlet is shut off. Notice both gauges show almost the same 70 psi:



Another thing I observed:
Check out the water pressure difference while flushing:

Water intake from piercing saddle valve:
Input gauge: 26 PSI
post-filters gauge: 13 PSI

Water intake from piercing saddle valve:
Input gauge: 62 PSI
post-filters gauge: 37 PSI

Which one will do a better job flushing the membrane?

Showing pressures while flushing:




But wait there is more!

So I have changed the membrane to the new one. The needle valve was useful while dialing down the target 4:1 wasteroduct water ratio Russ recommended for my hard water. It took a few back-and-forth adjustments but I was able to dial it to

• 250 ml/min product
• 1000 ml/min waste

PS: Talked to Russ about the precision on the flow adjustment valve being not so "precise". I observe that a tiny rotation makes a huge difference in water flow. I was expecting more precision. He said it is what it is and could be user error also. Well, it works for now. I guess I will try to find another flow adjustment valve which could do better.

Hey I just remembered this: I have a very precise flow adjustment valve for my CO2 injection system. I think I will look into getting one of those valves.


Anyway, I noticed that a tiny adjustment in the waste water flow adjustment also affects the product flow. Kinda makes sense, but also points out to the fact that input pressure matters a lot for reverse osmosis product. Here are the pressures while producing at the rate shown above:

Notice the 10 PSI drop over the filter blocks. Is that normal? Or does that mean my pre-filters are clogged?
Note that once the output solenoid closes, both pressure gauges show 70 PSI ...guessing that does not matter, but sill worth mentioning.




If anyone have two gauges like me, can you post a reading while producing RO water please?


Auto flush
Now I have an auto flush cycle programmed every hour for 2 minutes.
Is that good or I need to change this schedule?


Well, that is all for now!

Again, I will urge anyone with a RO system to check your water flow, just looking at your pressure gauge is NOT enough

 

[rajdude]

oh by the way here are some PPM readings. Taken around 45 minutes after new membrane installation, and after adjusting the flow to 4:1:

Input 190 PPM
Output 2 PPM

(I removed the DI stage a couple of days back, so not reading for DI)

 

[rajdude]

Raj - we have more flow restrictors at different flows if you still are looking for them.

Russ,
Thanks for chiming in here! I appreciate all your advice and patience with me

For me, I think the needle valve style flow restrictor I bought from you is ok for now. I cannot / do not want to go with a preset flow restrictor. I want to be able to change the ratio as and when needed.