TDS Problem with RO/DI Unit

[jrossjr79]

I just replaced all of my filters and membrane a month ago, doing 30 gallon water changes a month with 10 gallon a week top off. And already my TDS readings are out of whack, what can I do:


Tap: 216
Reject (after RO Membrane): 257 (btw after replacing everything it was only as low as 246)
After DI Resin: 3

[polarbear]

somthings off. Why would the TDS be higher after the membrane then the normal tap water?

[BBQHILLBILLY]

you can take out a good membrane, Ive done it before, you would think it would be ez to fix

Assuming everything is setup right.

[jrossjr79]

not sure, but it was higher even after replacing all filters, the membrane, then flushing it all for 10 mins.

I remember somebody saying I had the carbon and sediment backwards, could this be the problem, I left it the way it was cause that is how I originally bought it.
Right now its Tap > Carbon > sediment > membrane > DI Resin
.................................................. ....................>waste


you can take out a good membrane, Ive done it before, you would think it would be ez to fix

Assuming everything is setup right.

not sure what you mean by that post

[BBQHILLBILLY]

the sediment comes first. You may need to check your water pressure. Im just thinking. Should be checked.

[jrossjr79]

nvm, cant be that I have the two mixed up: http://www.nano-reef.com/topic/273910-mighty-mite-ro-system-installation/


the sediment comes first. You may need to check your water pressure. Im just thinking. Should be checked.

Started posting before your post went through, but according to the instructions at the site above, the carbon was suppose to go first. Does anyone have a spare water pressure checker that I can borrow for a second?

[Sherita]

Please post photos. Did you buy this unit used, or new? Your after membrane output is way out of parameter. You should be seeing a TDS of 3 to 5 after the membrane with 216 TDS going in.

Please post all information on the filtration system. Manufacturer, age, purchased new or used? GPD as well. Photos would be extremely helpful.

Has this until ever had a low TDS after the membrane. And do you have a bypass to allow for the flushing of the membrane before collection?

And, for the record, when replacing a membrane you need to flush for a minimum of 5 gallons of ro water.

Example params from my last round of TDS testing:

Input 276 TDS
after membrane 4 tds
after DI resin 0 TDS

Mine is set up like this: sediment>cat carbon>carbon block>carbon block>100gpd membrane>di resin

[jrossjr79]

Please post photos. Did you buy this unit used, or new? Your after membrane output is way out of parameter. You should be seeing a TDS of 3 to 5 after the membrane with 216 TDS going in.

Please post all information on the filtration system. Manufacturer, age, purchased new or used? GPD as well. Photos would be extremely helpful.

Has this until ever had a low TDS after the membrane. And do you have a bypass to allow for the flushing of the membrane before collection?

And, for the record, when replacing a membrane you need to flush for a minimum of 5 gallons of ro water.

Example params from my last round of TDS testing:

Input 276 TDS
after membrane 4 tds
after DI resin 0 TDS

Mine is set up like this: sediment>cat carbon>carbon block>carbon block>100gpd membrane>di resin

Sorry no way I can take photos right now, but here is all the information:

Bought used from member here on MAAST (bought from him last year)
2nd time I replaced everything on this unit (as far as filters and membrane)
Filters and membrane are now about a month and half old
50 GPD rated
Mighty Mite (sold from Air Water and Ice)
Never had a low TDS after membrane
if you mean by a flow restrictor to go to waste, yes there is one, if really meant a bypass for flushing so it does not go to DI resin, then no, but when flushed I had DI Resin disconnected.

According to manual for this unit setup is carbon then sediment then membrane then DI.

However I will soon, real soon, be slowly upgrading this unit to more GPD, and with Canister type Filtering instead of this inline tubing stuff. At that time I will be setting up with sediment first and carbon next.

[polarbear]

+1 to what Sherita said. Mines set up the same.

[Sherita]

I'm just curious, since you have never had a low TDS after the membrane, is it possible that you have an output line reversed? That's why I asked for photos. I've found that a lot of times I can stare at something and not see the problem, but when I show it to someone else, they spot the problem right away. Something isn't right, since you have never seen a low tds output from your membrane.

[jrossjr79]

kind of hard not to harness this one up right since right on the tubing it tells you which way the water is suppose to flow through it. As soon as the ipad is done charging I will take some photos though.

[Bill S]

Another thought. You replaced the membrane. These can be tricky to get to seat completely. I recall Russ from Buckeye saying that this is their number 1 problem.

[jrossjr79]

have not thought about that, I am sure it is completely seated, but will def take a look after dinner to see if that is the reason.

[Veni Vidi Vici]

Faulty TDS Test Equipment?

[BuckeyeHydro]

Did you get this squared away? The reason they have the sediment filter AFTER the carbon is that they are not using a carbon block, they are not even using a carbon filter designed to be a prefilter - it is a taste and odor filter designed to go between a pressure tank and a faucet - think very slow flow, and minimal gallons. On your system it is being used as a prefilter - beautiful:(. A taste and odor filter contains GAC - and GAC gives off carbon fines - that's why they have the sediment filter after.

We have never sold these sorts of mini systems into this hobby - and there is a reason for that. Cost of ownership is high, performance is low. Might be ok in a pinch to produce emergency drinking water, but IMO not a good fit for this hobby - unless maybe you have a micro-mini-nano goldfish bowl tank.

Russ

[jrossjr79]

Did you get this squared away? The reason they have the sediment filter AFTER the carbon is that they are not using a carbon block, they are not even using a carbon filter designed to be a prefilter - it is a taste and odor filter designed to go between a pressure tank and a faucet - think very slow flow, and minimal gallons. On your system it is being used as a prefilter - beautiful:(. A taste and odor filter contains GAC - and GAC gives off carbon fines - that's why they have the sediment filter after.

We have never sold these sorts of mini systems into this hobby - and there is a reason for that. Cost of ownership is high, performance is low. Might be ok in a pinch to produce emergency drinking water, but IMO not a good fit for this hobby - unless maybe you have a micro-mini-nano goldfish bowl tank.

Russ

Yes I got it all squared away, TDS is still higher than I like, but will be upgrading my RO/DI unit here soon.