Source water problems
- Thread starter demonspeedn
- Start date
- Tagged users None
chipmunkofdoom2
Always Making Something
No, ideally you only need to change the final mixed bed when the color changes. I mentioned that you might need to replace it because you've seen > 0 ppm TDS on your product water. It sounds like this was because the second cartridge, the anion resin was depleted. If that's the case, this means that all the heavy load placed on your single bed anion resin was then placed on the final mixed resin. If that's the case, the uncolored beads (the anion resin) in the mixed bed were most likely depleted and you'd have no way to tell based on color. The final mixed bed is designed to take the load from a functioning cation resin followed by a function anion resin. It was not designed to change colors if it is used without an anion resin, which sounds like effectively what happened.
If you change the anion resin very carefully every time it's depleted (ideally right before), then no, you don't need to add an another anion stage. I chose to do so, however, for the same reason we use two DI cartridges in traditional setups. Once the first depletes fully, there's still another full cartridge of anion to go through. I don't have to worry about any remaining capacity in the first cartridge, and I can use it until it's fully depleted.
60 PSI is fine for the TFC membranes we use in the hobby. Your prefilter setup is okay, but as I mentioned, I would change to a low micron sediment filter first next time around. The reason is because generally a 5 micron sediment filter only captures particles larger than 5 microns. That means your carbon blocks, with their 1 micron pores, now have to try to filter out the solids that the sediment filter let through. This clogs up the carbon blocks prematurely, which prevents them from doing their primary job (removing chlorine and chloramine). Carbon blocks are a relatively expensive way to remove particulate matter, while sediment filters are less so.
A 100GPD membrane is probably okay, and it sounds like your rejection rates are pretty good. I'd still consider using a 75 GPD membrane your next change. They'll likely give you better rejection rates and lighten the load on your DI resin.
Degassing setups don't need to be anything fancy. Usually they're just a container with an air stone and some RO water. Once the RO water has been aerated a while, you just pump it through your DI resin at a slow pace.
Also, consider placing a tee and a valve between your RO membrane and DI resin. When you first turn your unit on, allow the first 5 minutes of water or so to go down the drain before allowing it to go to the DI resin. As your RO membrane sits, the brine tends to osmose through the membrane and ends up in the product water, meaning the first few minutes of water out of your RO membrane have very high solids, which could also be burning up your DI resin.
OP
OP
demonspeedn
Active Member
Thank you.
Amoo
Professional Thread Derailer
@demonspeedn Regardless of where you live, you will have a county Ag extension. Take a sample of your water (right out of the tap) to them and they will send it off and have it tested by one of the state run labs or universities for around $10. It's a service they are required to provide IIRC.
This will tell you exactly how you need to setup your RODI to be most efficient. Well at least give you the info so you can figure it out. Or just post it on here and ask.
This will tell you exactly how you need to setup your RODI to be most efficient. Well at least give you the info so you can figure it out. Or just post it on here and ask.
OP
OP
demonspeedn
Active Member
If I change the membrane to a 75GPD, I assume I will have to change the flow restrictor to match, correct? I do have a valve before the resin to drain for a few minutes. Unfortunately, I'm not consistent using it.
Sounds like some fine tuning of the RODI system and a water test is in order.
OP
OP
demonspeedn
Active Member
That is good to know. I will give them a try. Thanks for the info.
chipmunkofdoom2
Always Making Something
That's likely correct. BRS recommends a 500 ml flow restrictor, but that's far too restrictive for a 75 GPD membrane. At least it was in my case. I have an 800 mL restrictor on my 75 GPD system and get just below a 4:1 ratio. If they sold you the system as a 100GPD and it already has an 800 ml restrictor, you might be okay with that.
The best option is a capillary valve, but you need to adjust those yourself. It's not difficult to do, but it's more work than just using a fixed restrictor.
Hi
Sorry for jumping in on the thread , I have had a problem with sps colonies stn over the last few months after the water authority flushed the pipes I have gone through the tank changing heaters pumps all the usul things chasing my tail the last thing to replace was the RO unit so I purchased a new one with filters and resin after 1 day the resin went pink and pink water was being produced ,the authority came out and took water samples 4 days ago and today rang saying the waters params were ok and it takes 10 days for a full report so I replaced the resin with the remainder that was left after the first filing and its stayed green and the tds is zero a icp test shows very high zinc anybody got any idea's as im stumped.
Bill
Sorry for jumping in on the thread , I have had a problem with sps colonies stn over the last few months after the water authority flushed the pipes I have gone through the tank changing heaters pumps all the usul things chasing my tail the last thing to replace was the RO unit so I purchased a new one with filters and resin after 1 day the resin went pink and pink water was being produced ,the authority came out and took water samples 4 days ago and today rang saying the waters params were ok and it takes 10 days for a full report so I replaced the resin with the remainder that was left after the first filing and its stayed green and the tds is zero a icp test shows very high zinc anybody got any idea's as im stumped.
Bill
First, your resin cartridge should be absolutely full, and packed very tightly. Your's isn't.
Second... sure looks like your getting that color from the resin, no? What brand of resin/what vendor are you using? That's where I'd start.
Second... sure looks like your getting that color from the resin, no? What brand of resin/what vendor are you using? That's where I'd start.
Checked with the supplier they have never had a problem been selling it for 10yrs or more ,I removed the pink stuff and cleaned it out and replaced it with the remainder of the packet as per the last pic and its stayed green and tds Zero just stumped at minute im using bought RO water . .
Buckeye
The resin is MB-115 colour change di resin for pure water applications .The RO unit and filters /resin 1 day old the resin changed to pink after running 250L only >I have had the remaining resin running for 3 hrs this afternoon and its still OK tds zero as per last pic.
The resin is MB-115 colour change di resin for pure water applications .The RO unit and filters /resin 1 day old the resin changed to pink after running 250L only >I have had the remaining resin running for 3 hrs this afternoon and its still OK tds zero as per last pic.
I don't know they have not produced a analyst report yet only verbally told it was within their params but what that means no idea . Do they do water test for serious stuff like bacteria first then analyse the water chemistry.
Amoo
Professional Thread Derailer
@maxwell As I suggested to the OP, I realize you have the local water authority who just came out and ran a test on your water, but you also have the option of taking a water sample to your local Ag Extension office and sending it out for a full analysis. Every county in the US should have one of these and this is a service they provide for somewhere in the neighborhood of $10.
They'll send it off and email/mail you a full report of everything that is in your water. I would highly recommend going this route as the extensions typically use state university labs to do their testing and you don't have to question if there are any bias in the results.
Not to say your local water authority wouldn't be honest with you, but stranger things have happened.
They'll send it off and email/mail you a full report of everything that is in your water. I would highly recommend going this route as the extensions typically use state university labs to do their testing and you don't have to question if there are any bias in the results.
Not to say your local water authority wouldn't be honest with you, but stranger things have happened.
Pot perm would be something that is purposefully added - it is a strong oxidant. They would have added it - not something they would need to test for. Do you have a pot perm filter in your house?
OK - you'd know it if you had one. Pot Perm is used as the strong oxidant for greensand filters for example - used to remove iron/manganese. Potassium Permanganate is an oddly vivid purple liquid when mixed with water - stains everything it touches. You'd know it if you had one.
I have found the lab doing the testing and emailed them with a full history of events and that I have samples of the pink water and resin available to test as they were not taken by my the local water services so will have to wait and see if they respond. many thanks for all the replies.
OP
OP
demonspeedn
Active Member
I talked to my local Ag extension. they only test for Nitrates, lead, Arsenic, and Bacteria at a cost of $25 each. I ordered an ICP test from ATI and am waiting for results from that.
