Ro Unit Pressure?

[proton]

Hi All, well I am currently filling my 165L tank with RO water. It is at the moment running and has been running all night and day and the tank is only 33% full. The pressure is 25psi, Is this enough? also how do I know the water going in there is nearly pure water, 98% pure or marine ready is what I mean. I have read the manual and it says that the PSI should be between around 40 me thinks, in order to get best results? has anyone else had the same problem? *reffered to manual, and now i'm confused*

It says 0-75psi pre-filter pressure for operation... And how or what can i used to measure the "Total Dissolved Solids" or TDS as it says in the manual.

 

[steelhealr]

Anything 45PSI and under is going to give you a dribble at best.

You need a TDS meter. SH

 

[SkiFletch]

Agree with SH. If your pressure is that low you may need a "booster pump" to bump it up.

 

[proton]

oh crap, what is a booter pump? yes I do have dribble at the mo, but i am in no rush, as all i have in the tank at the mo is some rocks and sand... LR will be coming only next week, so i just wanted to set it up and start the cycle period...

OK never mind I saw what a booster pump is, one costs about £50, that is a little pricey for me right now.
But ordered a TDS meter for £13. So that's me hoping. Do LFS test the TDS of water?

 

[AK77]

My LFS will do free water tests during the week (£2 at weekends), so your LFS might offer something similar.

 

[SkiFletch]

Yeah, depends on the LFS. The good ones will have a TDS meter on-hand .

There's no harm in using the RO unit at a low pressure, the flowrate just goes down

 

[proton]

Hi guys, I just received my TDS meter from fleabay and it reads 43 PPM, then 52 PPM, then 69 PPM, then 65 PPM. Ok knowing that it is not perfect, what does that actually mean? I'm confused? It doesn't say anything about it in my manual.

OK, I waited a minute and shook the TDS meter to get the water out and it read 40 PPM, so now that I know that, is it acceptable? Can I start adding the salt and LR?

 

[SkiFletch]

Where are you measuring this TDS of 40ppm?

Tapwater should be 100+
RO discharge should be <5 (assuming the tapwater input TDS is under say 300)
RO waste should be >tapwater
RO/DI output should be 0-1

If your RO water is higher than 5, something isn't right. The unit might need a flushing, the membrane might be spent, or it could be a function of too low a pressure.

 

[proton]

I was measuring it from the tank, I dipped it in the tank, and swired it around for 2 seconds and pulled it out. The water from my tap is 420 ppm. If all this is not ready, can I add in aquasafe to get rid of the rest of the purities before i proceed with adding live rock for filtering?

 

[AK77]

Hi,

I'm assuming that the reading of 40-60 ppm is the reading from the salt that is dissolved in the aquarium water? What you want to be testing is the RO water that comes out the machine. The RO water should be reading next to nothing. Its that which needs to have no dissolved chemicals in it. If the reading from the RO water is 0-1 then you are fine to mix with salt and add to the aquarium.

If the aquarium only has RO water in it, and you've added no sea salt to it, then you have a problem with the RO machine if the reading is 40-60 ppm. As Ski says, you either need to flush the filters, the membranes might be knackered or the low pressure is resulting in the improper functioning of the machine.

 

[SkiFletch]

Yeah, you have to test the RO water (before you mix it) with the TDS meter . Testing the TDS of saltwater is a little out of scale for these little TDS meters .

With a tapwater TDS of 400+ppm, you'll probably look at an RO TDS of around 10-20ppm. Gets tough to remove that many ions.

 

[proton]

OK this is bad it means I have to empty the tank and start again. This is the RO water that is in the tank. Does sticking your hand in there make it go up? I was installing the powerheads in there and my 2028 Eheim Filter, it was used in the freshwater aquarium, but has been cleaned, could that have increased it? I did a reading this morning and it is now at 230

I do have a DI part that is not attached to the unit. Do I need to attach it?

OK so this morning before I went to work, I installed the DI unit (it was very easy). I run it till I got a cup full. And Viola I had a ZERO reading so I have to run off, I'm sure the TDS in the tank could be cause I didn't have the DI unit on it.
Having a plumber coming to check my pipes this weekend. Maybe I could ask him to sort out the RO unit.

 

[AK77]

lol that would explain the problem then. Each stage of the RO machine removes more dissolved salts from the water. I don't know if you can "recycle" the water already in the aquarium and feed it back through the RO machine? The only other option if you can't do that, would be to pass the water through something like a Britta filter and see what the TDS is then. Although it'd be a lot easier if you got the pressure up on the RO machine - you could fill the tank in a day then lol

 

[SkiFletch]

Ok, thats cool that once you add the DI unit, the TDS drops to zero, but what is it when it comes out of the RO discharge before the DI unit? Thats a critical number right there...

 

[proton]

but what is it when it comes out of the RO discharge before the DI unit? Thats a critical number right there...

Oooo I dunno, Silly me where were my brains that day... Well I will need to test when it comes out before the DI unit.