Alkaline & PH very low

I woudl stop tinkering and leave the dousing pump out of the pool for a while.

Get some experience with testing and tracking your pH and TA without it being effected by any outside influences.

Record all your test results in PoolMath



What is confusing that your douser system was continuously adding acid and causing your pH and Ta problems? That is why we don't recommend those system. You never know when they go haywire.
Will do thanks. More trouble than it’s worth
 
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Really appreciate the advice but that’s way out of my league.
I would need to send it back to the company I bought it from but the last time I done that (2 weeks ago) they told me they had done full service and it was only the sensor . They even sent me a photo of the sensor with big crack in it (was not like that when I sent it to them!!).
I’m guessing they never serviced the pump at all, only done a calibration.
I think I should cut my losses and throw this Chinese stuff in the trash!
Oh Okay.

Then its unlikely it was siphoning. As a user you cant tell if the service has been completed.

If you need to continue using the dosing pump then one more test we can do to eliminate siphon is:
- fill the bucket with water.
-Turn dosing pump on manually and let it pump for a good 10-15 minutes make sure it is dosing water (Note this will also dosing some acid whatever is left in the dosing lines and dosing pump head).
- Turn off dosing pump and measure water level.

Now again wait and measure.
I just wonder if a siphon effect was to blame.
You have a different brand of equipment than most here use but perhaps reviewing some info from one of the more common US ones would be helpful as they likely all work in a similar fashion.

Dosing pumps in the USA are generally peristaltic. That is, they have a tube and roller system. Outside the USA, it is common to see positive displacement pumps, more commonly termed diaphragm pumps. The diaphragm pump is usually considered better for control etc. The Emaux pump the OP is using is a diaphragm dosing pump and works with check valves on the inlet, outlet and injector.
 
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I would stop tinkering and leave the dousing pump out of the pool for a while.

Get some experience with testing and tracking your pH and TA without it being effected by any outside influences.

Record all your test results in PoolMath



What is confusing that your douser system was continuously adding acid and causing your pH and Ta problems? That is why we don't recommend those system. You never know when they go haywire.
Checked the bucket of water this morning 1 hour after the pool pump started (bucket that the acid pump suction line was in) and the level was way down.
This confirms the dousing pump is faulty as it was in stop mode, yet fluid was still getting siphoned out.
As per suggestion from a poster, check valves likely sticking.
Will send it back for inspection and won’t be in any hurry to use it again!
 
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Checked the bucket of water this morning 1 hour after the pool pump started (bucket that the acid pump suction line was in) and the level was way down.
This confirms the dousing pump is faulty as it was in stop mode, yet fluid was still getting siphoned out.
As per suggestion from a poster, check valves likely sticking.
Will send it back for inspection and won’t be in any hurry to use it again!
What happens is the check valves get a bit of dirt in them and dont seat properly. This includes the injector. There are three sometimes four check valves in this type of dosing pump system.

Foot valve that goes in the liquid, inlet valve on bottom of the dosing head, outlet valve on discharge of dosing head and injector itself. Not as common in acid pumps, these valves get a bit of build up or crud under them and dont seal, more commonly on discharge side and this then allows the pump to siphon the liquid into the line rather than inject it.
 
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What happens is the check valves get a bit of dirt in them and dont seat properly. This includes the injector. There are three sometimes four check valves in this type of dosing pump system.

Foot valve that goes in the liquid, inlet valve on bottom of the dosing head, outlet valve on discharge of dosing head and injector itself. Not as common in acid pumps, these valves get a bit of build up or crud under them and dont seal, more commonly on discharge side and this then allows the pump to siphon the liquid into the line rather than inject it.
Thanks David, appreciate all the info. Will see what the company in Bangkok says about it.
 
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Back again with another issue…
After getting my acid dousing pump back and being told it’s working fine, I’m not having issues getting it to pump.
I’ve bled the system and it seems to work fine but as soon as tighten the suction and discharge fittings on the pump, it looses suction.
I slack off the fitting and it pumps fine again. Can do this multiple times with same result.
I have the discharge end disconnected from my pool pump line, so I can clearly see the water (using water until I solve the problem) starting and stopping being pumped.
I can’t risk leaving the fittings lose in fear of acid leaking out.
The so called engineer from the company I bought the pump from, is of no use to me at all.
He apparently checked and cleaned the valves.
As I mentioned, it seems to work as normal until I tighten (hand tight) the suction and discharge fittings, then no more fluid comes out the line.
Any ideas??
 
It wasn’t like that at all previously. Only since it was sent back to me.
That extra 1/4 turn is all it’s taking to stop the fluid coming out.
I’m quite sure with the pump running for a day or two, it would start leaking at the fittings.
I’ve emailed the company again to tell them I’m send everything back for a 3rd time. If they can’t fix it properly, then refund me for the new sensor and they can keep the pump.
Better off without it!!
 
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