Ro-Di

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RobLSU03

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So I got the 125g up and cycling fours days ago for the next three weeks while I'm offshore. Intial fill up used tap water
(I know I know) but that was my option. Used conditioner and running some carbon in the canister. Topping off with distilled for now. Will check the parameters when I return but tank seems to evaporating 3 to 4 gallons a day which I didn't expect but its open topped. How many GPD should I be looking into on the RO-DI I plan on installing when I get home. Thought I would had more time off to get one installed but works been crazy.
 

RobLSU03

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I'm a Spectrapure guy: Water Systems

But at the end of the day, they all work the same. You can mix & match any cartridge, membrane, DI resin, etc. with any unit.
Have made a decision on the ro yet but definitely looking at plumbing it directly into the ato. So much has advanced in the 13 years I took a break from the hobby I feel like I don't know anything again.
 

clsanchez77

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Have made a decision on the ro yet but definitely looking at plumbing it directly into the ato.
Let's talk that through before you go there ;).

There are two major concerns here: 1) Equipment failure causes the ATO to "Fail On" and kills your take and destroys your house and 2) the intermittent on/off cycling due to micro-dosing of RO water degrades the membrane performance AND quickly exhausts your DI due to a phenomena known as "TDS Creep".

The best way to solve problem one is to "air gap" the RODI from the tank so a Fail On does not flood the sump. This requires a storage container and a dedicated ATO pump. If the ATO pump fails on, you can only pump what is in your bucket. If you really don't want to do this (or can't), then you must include some kind of redundancy that is exterior to your ATO controller. For example, if you use a standard ATO system (pick a brand, any brand), a lot of them will use some kind of float or optical sensor that is connected to a powered unit and the powered unit controls a top off pump and/or RO/DI solenoid valve. If you have your RODI directly connected, I would plug the ATO into a controlled outlet that switches off if a mechanical float in your sump goes off. So if the ATO fails, you have another level of failure mitigation. Some ATO units have redundancy built in and some are higher quality than others. But at the end of the day, you are trusting thousands of dollars in investment to a single chip controller that costs a few tens of dollars at most. If you direct connect, have a backup.

The TDS creep is a little harder to understand and mitigate. Every time you shut the RO unit off, the TDS on the supply (intake) water and permeate (clean water) side will equalize. This is counter-intuitive, but it is because RO membranes are not "Filters", thus the salt/TDS can flow both ways across the membrane. It takes a pressure and flow to get clean water through the membrane without the salt. Remove either one and salt can easily go through the membrane. The only mitigation to this is either 1) never turn the system off :D, 2) waste the first gallon of RO permeate each time the unit turns on, or 3) batch your RO/DI water is large enough quantities that the first gallon of water having high TDS just is not significant. Sure, the DI resit will remove this TDS, but at the cost of exhausting your DI resin. In an automated setup where you cannot flush the water, you end up just spending a lot more money on DI beads. There is no consequence to your tank....just the wallet.

BTW, no RODI systems for sale in the hobby have any means to deal with TDS creep, you just have to replace the DI cartridges more often if you perform many smaller batches instead of fewer larger batches. I learned through experimenting that wasting that first gallon of permeate makes a huge difference in how long your DI lasts. I was working on automating that before Hurricane Ida forced me out of the hobby.

So much has advanced in the 13 years I took a break from the hobby I feel like I don't know anything again.
Yes and no. The equipment has come a long way, but the basics are exactly the same. Unfortunately, what I see is over time the equipment has gotten far more expensive despite more mass production and lower quality despite becoming more expensive. The fundamentals remain the same.
 

RobLSU03

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Let's talk that through before you go there ;).

There are two major concerns here: 1) Equipment failure causes the ATO to "Fail On" and kills your take and destroys your house and 2) the intermittent on/off cycling due to micro-dosing of RO water degrades the membrane performance AND quickly exhausts your DI due to a phenomena known as "TDS Creep".

The best way to solve problem one is to "air gap" the RODI from the tank so a Fail On does not flood the sump. This requires a storage container and a dedicated ATO pump. If the ATO pump fails on, you can only pump what is in your bucket. If you really don't want to do this (or can't), then you must include some kind of redundancy that is exterior to your ATO controller. For example, if you use a standard ATO system (pick a brand, any brand), a lot of them will use some kind of float or optical sensor that is connected to a powered unit and the powered unit controls a top off pump and/or RO/DI solenoid valve. If you have your RODI directly connected, I would plug the ATO into a controlled outlet that switches off if a mechanical float in your sump goes off. So if the ATO fails, you have another level of failure mitigation. Some ATO units have redundancy built in and some are higher quality than others. But at the end of the day, you are trusting thousands of dollars in investment to a single chip controller that costs a few tens of dollars at most. If you direct connect, have a backup.

The TDS creep is a little harder to understand and mitigate. Every time you shut the RO unit off, the TDS on the supply (intake) water and permeate (clean water) side will equalize. This is counter-intuitive, but it is because RO membranes are not "Filters", thus the salt/TDS can flow both ways across the membrane. It takes a pressure and flow to get clean water through the membrane without the salt. Remove either one and salt can easily go through the membrane. The only mitigation to this is either 1) never turn the system off :D, 2) waste the first gallon of RO permeate each time the unit turns on, or 3) batch your RO/DI water is large enough quantities that the first gallon of water having high TDS just is not significant. Sure, the DI resit will remove this TDS, but at the cost of exhausting your DI resin. In an automated setup where you cannot flush the water, you end up just spending a lot more money on DI beads. There is no consequence to your tank....just the wallet.

BTW, no RODI systems for sale in the hobby have any means to deal with TDS creep, you just have to replace the DI cartridges more often if you perform many smaller batches instead of fewer larger batches. I learned through experimenting that wasting that first gallon of permeate makes a huge difference in how long your DI lasts. I was working on automating that before Hurricane Ida forced me out of the hobby.


Yes and no. The equipment has come a long way, but the basics are exactly the same. Unfortunately, what I see is over time the equipment has gotten far more expensive despite more mass production and lower quality despite becoming more expensive. The fundamentals remain the same.
I really appreciate you taking the time to explain this. I'm very worried about a failure on ATO while I'm offshore being directly plumbed. The more research I will most like go with a good storage space for water. Looking at the Tunze 3155 for the ATO. I agree about the prices going up and feel like I should just stick with what I know and worked for me in the past instead of overloading myself and making a mistake. Again ty for the information.
 

clsanchez77

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No problem. I enjoy it. I just see people getting lost with all the new gadgets and you look at the big national boards, which are sponsored by the way, and it seems like there is always something else to buy that solves another problem and creates another one in the process. In exchange for that, most hobbyists no longer understand the fundamentals, just the LED light colors lol.

In the meantime, I am trying to find a float switch operated outlet that could be used to shutoff a solenoid valve that you would put upstream of the RODI unit and I cannot find it anymore. A whole new line of products since I last looked at this.
 

RobLSU03

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No problem. I enjoy it. I just see people getting lost with all the new gadgets and you look at the big national boards, which are sponsored by the way, and it seems like there is always something else to buy that solves another problem and creates another one in the process. In exchange for that, most hobbyists no longer understand the fundamentals, just the LED light colors lol.

In the meantime, I am trying to find a float switch operated outlet that could be used to shutoff a solenoid valve that you would put upstream of the RODI unit and I cannot find it anymore. A whole new line of products since I last looked at this.
I decided to go with a 6 stage RoDi at 75gpd from BRS. Automating everything scares me, I still would like an ATO(probably the Tunze 3155) but gonna store water in bulk think that will be the safest. So far I'm not I'm offshore but the wife says I'm averaging four to five gallons a day which I'm thinking is its open topped and the weather has been cold. I would like to cut the evaporation but I don't want tops so I'll deal. Also adding a sump not a fan of the canister it runs on currently but it's what it had when I purchased and I need more versatility. Just not sure how big of a sump to run, the one I'm looking at is a simple setup and hold 21g, not sure if that will accommodate a power outage or pump shutdown and also keep up with the evaporation rate. Trying to keep it simple but setup for a successful reef tank at the same time.
 

clsanchez77

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That is a good unit. I have the same one, but did the RO add-on to get the 150-gpd.

I dont think you need to fear automation, just need to understand what can go wrong and how to mitigate it. The Tunze ATO is the best and more reliable one out there, you are paying more for it, but getting what you paid for.

4-5 gallons a day is a lot. I was running a little over that in a week. I was averaging about a gallon a day on a 90-gallon tank, but still under 2 gallons a day even in the winter. But I like to hold at least a week in topoff, so I would suggest 40 gallons...which is a lot. I ran my RO/DI only on Sunday, because I'm typically home and could watch it, but also when I was planning to automate it, I knew I would not have a situation where topoff pump was stuck on and the reservoir was not being infinitely topped off.

I would suggest a sump. Is your tank an AIO? Or just a 125-g running a cannister? If so, you will probably want to add a skimmer soon and you will need a sump for any reasonable skimmer options. If you don't want a skimmer, you will still need a sump for any of the alternate filtration options. Also a great place for heaters and top off water.

An aquarium top will reduce evaporation, but at the expense of the aquarium will run hotter. Evaporation cools the water temperature down, but quite a bit actually. So just be aware of the trade-off.

Trying to keep it simple but setup for a successful reef tank at the same time.

Yes, simple is better :) Complicated is fun, until something breaks.
 

clsanchez77

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That sump is nice. I have found the Trigger Systems sumps to be very well built. I loved my Emerald 34 and I have a new Triton 44 in the garage waiting on a new tank.
 
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