YOUR CURIOUSLY INNOCENT NEGLIGENCE

[Battlecorals]

This is excellent news man Really glad to hear things are turning around for you

Hello Adam, Sorry for the lack of updates, work has been nuts. All healthy acros are showing better, more consistent PE. Tissues look fatter and healthier. Struggling frags are still struggling but not getting worse. Overall I'm happy with the change but I cannot rid the tank of cyano at this time. I have been very limited on time so just bearing with it till things get a little easier then I'll attack it in earnest. I have yet to add any new acros since the change so I don't know of a healthy new intro would continue being healthy. I'll get back to buying corals soon and we'll see.

This is excellent news man Really glad to hear things are turning around for you

 

[Black Pearl]

Adam, back in post #18 you asked

Quick question, are you by any chance running dual serial membrane system?

Could you address this further, I am running dual series membranes, Thanks

 

[Maacc]

Adam, back in post #18 you asked

Could you address this further, I am running dual series membranes, Thanks

Adam has helped me with this in the past. He can definitely ammend if I have something crossed, but essentially even with good pressure when done in series with a flow restrictor sized for a single membrane (as the water saver setups are) over time the RO membranes do not flush properly and you get random contaminants slipping through that are hard to quantify, but the tank has strange problems that are hard to pin down.

 

[Black Pearl]

Thanks for the response, but it raises another question. Do you just change to another restrictor or is the dual in series a bad idea altogether

 

[Maacc]

On Adam's advice I just got rid of it. If you do the bigger restrictor you may as well run it in parallel, because that is how it acts functionally.

 

[Battlecorals]

Adam, back in post #18 you asked

Could you address this further, I am running dual series membranes, Thanks

Hi there, really sorry for the delay on this one man.


What I know about running dual membrane systems I learned mostly from our very own AZdesertrat, who is extremely knowledgeable on the subject. But i did run into my own issues years back as well, which is what lead me to research them in the first place.

Ultimately its simple as this, And AZ has said it many time on the forums, and has away better explanation even, but it comes down to these points: For a tfc membrane to function properly, you really want to flush at least 3 gallons over the membrane, preferably 4 to every 1 gallon of product water during operation. This will ensure that the membrane is kept at optimal performance levels. When you run dual membranes in serial, where you take the waste from one and run it into the second you are squashing that ratio to 2:1 or sometimes even 1:1. And while this will save water, the potential for either membrane to foul is much higher, which can be a real problem.

To really save water, which is primarily the reason most people use the dual membrane systems, the best option, and please understand that i have no affiliation with these guys, but the Spectrapure UHE RO/DI systems are the only safe way to run a a system at 1:1.

My advice would be to simply run the single membrane with at least a 3:1 product ratio. and keep the second membrane on hand for when you need to swap out the old one. If you'd like any other details on the flow restrictor tuning, or any details at all, please shoot me a PM and ill be more than happy to go over everything I know

 

[Battlecorals]

Just to add to this discussion, I agree in general with Adam's assertions. Starting with good water is an absolute necessity. However, sometimes it is the saltmix! I bought a box of HW that was extremely low in K and it killed a few of my prized BC specimens before I could figure out what was going on. Acros were the least happy with the low K levels, the other corals seemed to tolerate it much more easily. Again, I am agreeing with Adam, but it is good to examine everything else that you can if you are sure that you are starting with the fundamentals (water source, flow, major ion levels and stability, acceptable light, etc.) and you are still seeing mysterious results. I started a thread about the K level in the Chemistry forum:

https://www.reef2reef.com/threads/hw-and-potassium.307204/

This is a very good point. Certainly there are instances where the salt may be the culprit. I once found a thumb sized piece of solid rust in a bucket of salt years ago. No idea how it got there, but it was in there.

Curious, how did you ultimately discover the salt was your issue?

 

[Scott.h]

If re-routing the waste water through a second membrane exits with a total tds of 2 by way of a 2:1 ratio, yet still has to pass through the DI, wouldn't the only harm be using more DI resin? It's my understanding that DI resin alone will almost purify water after carbon and a particle filter. I'm wondering what I'm missing? If the end product is zero are you suggesting impurities are still in the water due to recycling waste water through a second membrane?

 

[Velcro]

This is a very good point. Certainly there are instances where the salt may be the culprit. I once found a thumb sized piece of solid rust in a bucket of salt years ago. No idea how it got there, but it was in there.

Curious, how did you ultimately discover the salt was your issue?

Free GFO!!!!!!!

 

[Battlecorals]

If re-routing the waste water through a second membrane exits with a total tds of 2 by way of a 2:1 ratio, yet still has to pass through the DI, wouldn't the only harm be using more DI resin? It's my understanding that DI resin alone will almost purify water after carbon and a particle filter. I'm wondering what I'm missing? If the end product is zero are you suggesting impurities are still in the water due to recycling waste water through a second membrane?

Hi there,

Great question. The problem with this setup is that we're still squashing the waste ratio of the first membrane as well, not allowing a proper continuous flush during operation. This can serve to foul a membrane. I'm not saying it will happen every time or at all even, but the risk for problems is there enough that I wouldn't chance it. As well it's very unlikely that the waste tds would be that low. Normally the waste would actually be more concentrated than the original tap water resulting in a higher tds. For example if your tap water was 300 it's likely that the waste water would be as much as 325 or more because 1 pure gallon out of every 3 gallons has been removed in the process.

 

[rushbattle]

This is a very good point. Certainly there are instances where the salt may be the culprit. I once found a thumb sized piece of solid rust in a bucket of salt years ago. No idea how it got there, but it was in there.

Curious, how did you ultimately discover the salt was your issue?

I tested K with a salifert kit. I thought I had a bad kit, so I sent a test sample to Triton. They matched exactly the K level I measured with Salifert kit.

Incidentally, the rest of my Battlecorals were doing really well after I raised K to the proper level until Hurricane Harvey took out my power for a bit longer than my batt backup ran, and we were in a controlled zone for re-entry after the storm. Lost all of them. All of my other corals were fine though. I need to stock back up on BC once I am sure the tank is stable again.

 

[Scott.h]

Hi there,

Great question. The problem with this setup is that we're still squashing the waste ratio of the first membrane as well, not allowing a proper continuous flush during operation. This can serve to foul a membrane. I'm not saying it will happen every time or at all even, but the risk for problems is there enough that I wouldn't chance it. As well it's very unlikely that the waste tds would be that low. Normally the waste would actually be more concentrated than the original tap water resulting in a higher tds. For example if your tap water was 300 it's likely that the waste water would be as much as 325 or more because 1 pure gallon out of every 3 gallons has been removed in the process.

It's definitely better safe then sorry. From a purely scientific study would my reasoning be correct here? If someone had a natural tds of 100, recycled that waste water with a second membrane creating a 4:1 to 2:1, would they be better off then someone that had a 4:1 flush on a single membrane, yet started out with a higher natural tds of say 300?

 

[Battlecorals]

It's definitely better safe then sorry. From a purely scientific study would my reasoning be correct here? If someone had a natural tds of 100, recycled that waste water with a second membrane creating a 4:1 to 2:1, would they be better off then someone that had a 4:1 flush on a single membrane, yet started out with a higher natural tds of say 300?

Ultimately no I’d say. What would the purpose of the second membrane be in this instance? The efficiency wouldn’t really be increased if you were still running 4:1 through the first.

Likewise the waste tds from that membrane would more than the tap so really running the waste at 2:1 through the second would still very much run the risk of membrane failure.


If anyone can elaborate on this point, please feel free to so, as well if my information in not 100% correct, please correct me.

 

[Scott.h]

Ultimately no I’d say. What would the purpose of the second membrane be in this instance? The efficiency wouldn’t really be increased if you were still running 4:1 through the first.

Likewise the waste tds from that membrane would more than the tap so really running the waste at 2:1 through the second would still very much run the risk of membrane failure.


If anyone can elaborate on this point, please feel free to so, as well if my information in not 100% correct, please correct me.

I'm not sure either. It's kind of splitting hairs on stuff we can't generally test for.

What I meant - if you start out with a 4:1 waste gate. (4 gal waste/1 gal good) Take the 4 gallons of slightly higher tds then the original tds and run it through another 4:1 waste gate. The end result is cutting the waste in half and doubling the good water. (2:1.. heck I don't know). I just figured if I was starting out with tds around 105 I'd be ok, or better then someone with high tds. My tds meter is before the DI but after the second membrane. It's generally 1 or 2 before the DI.

@AZDesertRat you still around??

 

[Battlecorals]

I'm not sure either. It's kind of splitting hairs on stuff we can't generally test for.

What I meant - if you start out with a 4:1 waste gate. (4 gal waste/1 gal good) Take the 4 gallons of slightly higher tds then the original tds and run it through another 4:1 waste gate. The end result is cutting the waste in half and doubling the good water. (2:1.. heck I don't know). I just figured if I was starting out with tds around 105 I'd be ok, or better then someone with high tds. My tds meter is before the DI but after the second membrane. It's generally 1 or 2 before the DI.

@AZDesertRat you still around??

Well, my real question for you is, what are you trying to accomplish with the dual membrane system? Would the primary concern be trying to conserve water, or to make more water at time, or something else even? If your tds is under 200 (id consider 100 to be really low by most comparisons) and you had a softener, you could easily get by running 3:1 and that would safely increase your production, and reduce waste far better than running a dual membrane in serial configuration.

 

[Scott.h]

Well, my real question for you is, what are you trying to accomplish with the dual membrane system? Would the primary concern be trying to conserve water, or to make more water at time, or something else even? If your tds is under 200 (id consider 100 to be really low by most comparisons) and you had a softener, you could easily get by running 3:1 and that would safely increase your production, and reduce waste far better than running a dual membrane in serial configuration.

It's purely money savings. I do have a softener, as well as a whole house carbon filter, and a 5 micron house filter. My tds pre all of that is 106 ish. I think you are right though, changing my 4:1 to a 3:1 would be a safe compromise and eliminate the risk of pushing the envelope with that second membrane. On top of that I think I'll add a second DI canister increasing contact time. With not doing water changes at all my top off water is really important!

 

[Jeremy Luke]

Not long ago, I returned from a business trip to find a red/brown algae covering my tank. I mean covering. I could not figure out why as my parameters were solid before leaving and they were in line upon my return. I did a large water change. Things were not improving. I did another with the same result. I reflected back on this article. I once again check the inline TDS readings on my RODI system. The result, 0. Nevertheless this article stuck was stuck in my mind so I quickly ordered replacement media for my RODI system and paid extra to have it shipped 2nd day delivery. I replaced the media and did another large water change. The algae problem that was taking over my tank was running for the hills the very next day. Within two days it was gone. I'm not sure why I was not getting any reading from the inline TDS meters, perhaps they need to be replaced. Very thankful for this article though.

 

[Battlecorals]

Not long ago, I returned from a business trip to find a red/brown algae covering my tank. I mean covering. I could not figure out why as my parameters were solid before leaving and they were in line upon my return. I did a large water change. Things were not improving. I did another with the same result. I reflected back on this article. I once again check the inline TDS readings on my RODI system. The result, 0. Nevertheless this article stuck was stuck in my mind so I quickly ordered replacement media for my RODI system and paid extra to have it shipped 2nd day delivery. I replaced the media and did another large water change. The algae problem that was taking over my tank was running for the hills the very next day. Within two days it was gone. I'm not sure why I was not getting any reading from the inline TDS meters, perhaps they need to be replaced. Very thankful for this article though.

Really sorry to hear about the tank woes, But I'll confess that if my ramblings were able help even just one person, then it's certainly something I'll keep at. Glad to hear things cleared up for you. I do know that there are certain contaminants that will not show up on tds meters. curious though, what kind of TDS meters are you using? As in hand held, or inline?

 

[Jeremy Luke]

Really sorry to hear about the tank woes, But I'll confess that if my ramblings were able help even just one person, then it's certainly something I'll keep at. Glad to hear things cleared up for you. I do know that there are certain contaminants that will not show up on tds meters. curious though, what kind of TDS meters are you using? As in hand held, or inline?

Apologies for the late response. Work's been crazy and I hadn't checked my alerts. The TDS meters are inline on the RODI unit (BRS 6 stage setup with meters)

 

[niQo]

This makes me wonder if I should be replacing some filters...

My parameters are within range, but do have an ugly amount of GHA, some corals do okay, but nothing is thriving... most SPS STN over time. Some LPS not happy either

TDS after DI is 1.

At the very least I should be changing the DI.

Are you still supposed to flush the RO membrane when you use it multiple times s day?