What are acceptable readings for TDS

[sevenkillers]

I have been having problems with algae on my sand.
I checked my water for phosphates, and it came out zero.
Checked all of my ammonia levels, nitrite, nitrates are all zero.
just recieved my tds meter from Kent marine.
It said my TDS are 116 ppm coming out of my RO water.
The R.O unit is about two months old. I purchased it from ebay.

[Spuds725]

Is it RO only or RO/DI??

First-- check your raw water and see what that is--

When you check your RO water, let it run a bit before ckecking the water as you can get a bad "slug" of water when it first starts-- post back your results but you will probably get better help in the equipment forum--

although Randy has wrote about depleted DI resin causing high TDS from the resin releasing stuff, I don't know how strong he is in the hardware part of the hobby...

here is his article-- http://www.reefkeeping.com/issues/2005-05/rhf/index.php#8


Some of the ebay units have very poor DI stages-- too small and they don't distribute the water well enough to evenly to use up the resin-- this is easily remedied by getting an add on DI stage---

to answer your question-- the TDS for ro/di should be 0-- for RO it should be anywhere from 10% to 2% of your raw water (depends on the rejection of the membrane and some other factors)

[bertoni]

What is the TDS of the tapwater? 116 ppm sounds like the RO filter isn't working.

[EricM]

My TDS is always 0, starting with tap about 250. Replace the DI resin every six months or so when the TDS goes above zero. If the TDS starts going up more frequently than that you probably need a new RO membrane. Get a dowtech from buckeye field supply.

[sevenkillers]

<a href=showthread.php?s=&postid=8521708#post8521708 target=_blank>Originally posted</a> by bertoni
What is the TDS of the tapwater? 116 ppm sounds like the RO filter isn't working.

My incoming TDS is almost the same as the output just slightly higher.

[sevenkillers]

Going to get a new membrane.
thanks for the link to that article
I am also going to add a DI cartidge to the system

[Randy Holmes-Farley]

Sounds like a good plan, although the algae may be due to other reasons as well. I'd suggest seeing what that does, and if it is not solving the algae problem, then look to more nutrient export (despite the low readings).
These may help:

Phosphate and the Reef Aquarium
http://reefkeeping.com/issues/2006-09/rhf/index.php

Nitrate in the Reef Aquarium
http://www.advancedaquarist.com/issues/august2003/chem.htm

[Buckeye Hydro]

<a href=showthread.php?s=&postid=8522641#post8522641 target=_blank>Originally posted</a> by sevenkillers
My incoming TDS is almost the same as the output just slightly higher.

You mentioned your system is new. I'm not sure from what's been written here if you have an RO or RO/DI.

Because your system is new, and appears to be doing nothing to improve water quality, I'll take a wild guess here - are you sure you have the membrane installed in the system?

Russ @ BFS

[Buckeye Hydro]

<a href=showthread.php?s=&postid=8521329#post8521329 target=_blank>Originally posted</a> by Spuds725
although Randy has wrote about depleted DI resin causing high TDS from the resin releasing stuff, I don't know how strong he is in the hardware part of the hobby...

You can count on the advice Randy provides re RO/DI systems!

If there is something he's not sure of he'll let you know.

Russ @ BFS

[Spuds725]

I only quantified that as I know there are some hardware experts regarding RO/DI (including some vendors) in the equipment section.... IMO that would be a better place to ask hardware questions... Randy gets enough questions regarding chemistry ;)

Nearly 48,000 posts :eek1:

//edit//

oops... didn't see you are one of the vendors... :p

[192clark]

What could one expect from well water that has a TDS of 670. Not meaning to break in here but will this effect the life of the RO/DI filters?

[Randy Holmes-Farley]

The higher the incoming TDS, the faster the DI will be depleted in a given setup. Very roughly, double the TDS means half the lifetime (in gallons produced). 670 ppm TDS is medium high compared to typical city water.

The life of the sediment and the carbon filters depends on, not surprisingly, sediment more than TDS.

[Buckeye Hydro]

You may also experience a shorter life span for your RO membrane with water as hard as you describe.

[sevenkillers]

Since we are on this topic. Does radon in the water have any affect on Ro/Di?
Or to the reef tank?

I had a high reading of radon. I was still using a batch of water that I made up. Since then I purchsed a bubbler that removes radon from my water.

it cost me about 2800 for the machine.

[BLockamon]

Unless the Radon is REALLY high, I doubt you'll have a problem with the tank. I assume your water measured positive for Radon-222, which has a half life of ~3.8 days. It will essentially be all gone in ~26 days. If it's any of the other isotopes, it will be gone in a matter of seconds.

Radon is an Alpha emitter that is really only a hazard if it's inhaled. I'm not sure what would happen with a fish. Some dose to the gills I guess, but any water in the area would block Alpha almost instantly.

[korbynlehr]

Okay stupid question here, what is TDS?

[Fastmarc]

<a href=showthread.php?s=&postid=8531869#post8531869 target=_blank>Originally posted</a> by korbynlehr
Okay stupid question here, what is TDS?
Here's a good read for yah.

What is TDS?
http://www.reefkeeping.com/issues/2...ature/index.htm

[korbynlehr]

Thanks for the link but it doesn't work. I will try to do a search and see what I can find there. If you can please post a good link and that might save me and someone else a little time.

THANKS

[Fastmarc]

Hmm.... you're right.
Hopefully Randy can get it fixed as it is a good article.

[bertoni]

http://www.reefkeeping.com/issues/2004-04/rhf/feature/index.php

The link was cut and pasted improperly.

[Fastmarc]

<a href=showthread.php?s=&postid=8538727#post8538727 target=_blank>Originally posted</a> by bertoni
The link was cut and pasted improperly.
Oops.... my bad.;)

[Tigger240]

Just be sure to get a DOW Filmetc brand ro membrane ( i reccomend a 75 gpd b/c of a 98% rejection rate - the 100 gpd has a 90% rejection rate). I paid out the wazoo ($200) for a unit from the lfs and got a crap ro membrane. inlet was liek 135 and output was 70 something. I replaced the filters and ro and added a nice di and chlormine prefilter and inlet (when i tested) was like 135 and after prefilters was slightly higher (im guessing some carbon dust) like 145ish and after the ro itself was down to 1 to 2 tds. you can build a correct unit for about 150 ish have about a 7 stage unit. (just be sure - no matter what - to step down the micron rating for example - 10 micron sediment then 5 micron carbon block then a 1 micron carbon block. if you just run a 1 micron as your first filter it will fill up fast.)

As long as you keep chlorine and chlormines away from the ro membrane - they can last 3-5 years. di resin is replaced upon exhaustion or color change. if you keep a reef you should have a tds meter or a high end condutivity probe or both. you can buy a test kit to test your active carbon (the pre filter stage for me - i know its redundant as well)(salfiert carbon test kit) but should be replaced around every 6 months depending upon water usage. also clear prefilter housings are nice to visiually check the condition of your filters. h20supply has awesome prices on em.

[Buckeye Hydro]

<a href=showthread.php?s=&postid=8542845#post8542845 target=_blank>Originally posted</a> by Tigger240
(just be sure - no matter what - to step down the micron rating for example - 10 micron sediment then 5 micron carbon block then a 1 micron carbon block. if you just run a 1 micron as your first filter it will fill up fast.)



The "step down approach" a good one, but the approach should end with the sediment filters. Otherwise you are essentially using your carbon block as a sediment filter. It will do that just fine - but that's not the job you want the block to do.

Many, many people use a 1 micron sediment filter as the first stage successfully.

Russ @ BFS

[sevenkillers]

I have a whole house filter that starts from 50 microns down to .05 micron in the middle.
So I am sure nothing is getting near my r.o system.
The reason for that filter is for my Radon unit removal system.