RO/DI Question for RedFishBlueFish

[radiata]

I know RedFishBlueFish is a big fan of flushing RO membranes, hence the following:

How long, either in seconds or minutes, should an RO membrane be flushed before use?

I just converted my manual RO/DI to an automatic one with an Avast Barrel Tender V2 and a pressure switch for my Aquatec 8800 pump. So, I've lost my ability to manually flush the membrane before each manually started use. If I automate the flush, how long should the flush be for?

 

[redfishbluefish]

Just to be clear Bob, two meanings to "flush"

1. Divert water past the restrictor to back-flush the membrane. Typcially the manual ones look like this:

2. Divert water past the DI resin to allow breakthrough TDS to go to waste. The diverter valve from BRS looks like this.

With back-flushing the membrane, there are some who say it does nothing. However, I use mine to flush the membrane.....for about a minute on each startup.....but also use it when I'm done making water, open it up to take pressure off the membrane (with the intent of minimizing breakthrough....but this is just speculation if it works.....makes me feel good.)

With diverting, I've found for my membrane and tubing arrangement, that five minutes is enough to wash out the high TDS breakthrough....I've seen it shoot up to 50-60 TDS on this flush. This typically gets me to 2 TDS, at which point I flip the valve to direct water through my DI resin. I get over a year out of my resin by doing this.

Hope this answers your question.

 

[art13]

BRS builds the flush valves into the restrictors now paul, no more need for the splitter and additional valve. Automatic ones are pretty neat, BRS recommends 2 minutes before and after, about what i usually do mine for. 5 minutes like paul said gets him to much less tds, just a bit more waste water, if you have in line tds meters it makes it easier to figure out, i have 4 hooked up on mine.

 

[Mark...]

I flush about 2 mins before and after each water making session of 25 gallons.

 

[redfishbluefish]

I just checked out the all-in-one flush valves.....pretty neat:

I paid more for my flush kit, that didn't include the restrictor....and not only that, had to replace the valve about six months ago that cost me the same for these new flush valves. I wish I knew about these then.

I also looked at the automated flush kits and I'll stick with the manual kit. Didn't like that it was yet another electrical piece of equipement to plug in. The one I looked up flushed for 18 seconds every hour. Again, I'm good at the beginning and end of my water making day by simply manually turning that valve.

If I were to automate anything on my water making, it would be that flush-to-waste after the membrane, but before the DI resin. I'm not aware of anyone who has automated that, but I would thing easy enough to DIY if you wanted to.....but for me, not worth the 50-100 bucks.

Here's my routine now. WIth the flush valve open and the diverter valve going to waste, I turn on the water and the booster pump. I let that run for a minute or so and then shut the flush valve. I go upstairs and start the timer for five minutes. After 5 minutes, I check the TDS (dual meter before and after DI), and if it's 2 TDS or less, I'll flip the diverter valve to start running water through the DI and into my collection jug. Now I set the timer for 99.99 minutes (time to fill five gallons.)

 

[Jeremy Brito]

so i know im pretty late to the party but RO/DI is new to me its only a term i learned about a year ago . I know it should be used in marine tanks and for most fish keeping in general fresh or salt, but the process and the system i could use a little lesson on if you have the time to give me some basic knowledge or at least direct me to a place were i can obtain alittle education about ro/di . as it stands i dont have a system in my house i have well water and i herd its rough on ro/di systems but thats about all i know

 

[njtiger24 aquariums]

so i know im pretty late to the party but RO/DI is new to me its only a term i learned about a year ago . I know it should be used in marine tanks and for most fish keeping in general fresh or salt, but the process and the system i could use a little lesson on if you have the time to give me some basic knowledge or at least direct me to a place were i can obtain alittle education about ro/di . as it stands i dont have a system in my house i have well water and i herd its rough on ro/di systems but thats about all i know

Hope some more educated people can provide better answer here but here my understanding.

Our homes water (well or city) normally is treated with chemicals before reaching our taps. There TDS (total dissolved solids) in our water. Depending where you are and what you have will determine your TDS levels. These levels are normally ok for us for drinking but are not OK for our fish. Now some freshwater fish need some TDS but that is a different story. A RO/DI system strips (the best it can) the TDS and treated chemicals from our water making it safer for our tanks. I heard people having TDS up to 150ppm or more. Now just recently I purchased a handle held TDS meter (I had one build on my RO/Di unit but wanted to check and make sure it was working correctly). I had a reading of 40ppm from my tap and a reading of 24ppm when I read my Brita water filter but 0ppm on my RO/Do water. Hopefully that some good information for you lol