TDS too high

[CosmicDrift]

Hello,

the TDS reading from our watermaker has always been >500ppm and sometimes up to 880ppm. Testing water from other sources with the same meter typically is <300ppm so it is assumed the meter is ok.

Lowering the flow rate does not seem to help the TDS. Every effort has been made to follow the manufacturers instructions.

Is there anything that can be done to improve the TDS eg. cleaning, acid wash, etc or are the membranes just not any good?

Thankyou

[Captain Bill]

What kind of water maker?

[CosmicDrift]

It is a H2OToGo 12v/20lph.

[a64pilot]

We do need more info, but high TDS probably the membranes are shot.
Scaling etc that an acid wash helps decreases production rate but does little for TDS.
Except for maybe a bad O-ring in the membrane canister, I know of nothing that will drive TDS up,except membranes, many things will decrease production, but TDS being high is usually membranes.
Call the manufacturer and ask for their advice though first.

I’ve been wrong before

[Captain Bill]

I couldn't find that unit on the internet, is it manual or automatic? What pressure do you run? What kind of pump does it use?

[FlyingScot]

As stated, it's the membrane unless something is contaminating it after the fact.

[CosmicDrift]

Originally Posted by Captain Bill

I couldn't find that unit on the internet, is it manual or automatic? What pressure do you run? What kind of pump does it use?

It is manual, runs at about 700psi, sometimes up to 800psi. The pump is a 12v Pumptec 80940

[CosmicDrift]

Thankyou everyone, I will try to check the o-rings.

[CosmicDrift]

Maybe H2Oonthego

[belizesailor]

You say its always been greater than 500 PPM, thats is a bit high in most cases if memberane is in good shape (regardless of make/model). Have you verified that with another porperly calibrated hand held meter? Maybe its a calibration issue. How old is the membrane?

800 is above levels recommended by WHO etc for regular human consumption.

If bad membrane, in my experience, cleaning may make a temporary difference, but its usually new membrane time.

Bad seals etc could cause pressure drops which would cause high PPMs. Do you have gauges in the system or anyway to test pressures at critical points?

[Sailmonkey]

Are you getting any air into the system while operating? That can increase salt pass through.

[CosmicDrift]

Originally Posted by Captain Bill

I couldn't find that unit on the internet, is it manual or automatic? What pressure do you run? What kind of pump does it use?

It is manual, runs at about 700psi, sometimes up to 800psi. The pump is a 12v Pumptec

[CosmicDrift]

Originally Posted by Sailmonkey

Are you getting any air into the system while operating? That can increase salt pass through.

Yes, air bubbles randomly appear in the flow meter

[Pitchondesign]

I had high TDS and it was the o-rings in the canister as A64 suggested. Changing the canister o-rings is cheap. If you do change the o-rings, use silicon grease, not petroleum grease. Petroleum grease can cause premature failure of the o-rings and possibly contaminate the membrane.

Have fun.

[Captain Bill]

My water maker is manual and I see much worse TDS readings when running below 800 and improved readings running at 900. I don't know what your pump and pressure vessel are rated for so I can't recommend that you run it at higher pressure but it may help if you can. Your membrane may well be old and that's all it can do in it's present condition.