Sanitatizing Fill Off Irrigation Line

[ol_whistle_britches]

I inherited a pool fill that was plumbed in with superb southern ingenuity. It has finally cracked. In replumbing the autofill line, rather than go back to the old system, which filled off city water, (TA90, CH 125, pH 8.1), I would like to plumb it to my irrigation system, which has a zone within 10 feet. My irrigation source is from a large tributary that runs through my back yard with fresh river water.

I understand this is possible and some of you fill from ponds and other similar sources. Do you treat the incoming fill water before the pool? I’m not too worried about solids, (easy enough to filter) but I know there will be algae in that water to some degree or another. The pool will kill it as it’s introduced, as I understand it, but I’m wondering whether or not I’m gonna have a gunky pool fill chamber or some other unthought of side effect. Wondering if I should add a little UV sterilizer to kill algae before it gets into the autofill. Maybe I’m overthinking it.

I’m dosing LC daily right now, but I intend to convert to SWG this summer after the home warranty lapses.

Anyone else with relevant experience would be greatly appreciated.

Edit: tagging @duraleigh in.

 

[gkw4815]

I fill my pool with one zone of my sprinkler system. No water quality issues observed (at least none that can be attributed to fill water quality) over the couple of years that this setup has been in place.

 

[ol_whistle_britches]

I fill my pool with one zone of my sprinkler system. No water quality issues observed (at least none that can be attributed to fill water quality) over the couple of years that this setup has been in place.

Looking at your location, are you filling off of city treated water or untreated? City water has been sanitized.

 

[gkw4815]

Oops, sorry, I missed that part.

I'd think you'd be okay as long as you keep proper chlorine levels maintained in the pool, but will defer to the experts.

 

[Newdude]

would like to plumb it to my irrigation system, which has a zone within 10 feet.

Its alot more complicated than having a zone out there. I have questions before we talk about treating the water.

1) Are you ok losing the 'auto' aspect of the autofill ? It won't work without the irrigation pump running.

2) is the pool area zone going to be dedicated to the pool ?

3) if not, where/how are you splitting it and how will you control it ?

4) statement : the irrigation pump becomes a pool pump at this point and needs to be bonded with everything else and GFCI'd.

 

[ol_whistle_britches]

1) Are you ok losing the 'auto' aspect of the autofill ? It won't work without the irrigation pump running.

I think it will be “auto” enough for daily maintenance. My auto fill is just a toilet tank fill valve. I don’t know exactly how much evaporation loss I have each day, but I don’t think its enough to overwhelm the zone cycle time. If it is, I’ll just give it a dedicated zone. I don’t really care if my water level fluctuates .25” because the autofill only comes on for a limited amount of time every day or two.

2) is the pool area zone going to be dedicated to the pool ?

Ideally, yes. I’ll probably start by just teeing off the existing flower bed zone to get started, but eventually it could very well end up on its own zone.

3) if not, where/how are you splitting it and how will you control it ?

Initially, as described above. Tee the flower bed zone and let the fill run when the flower beds get watered. (I live in a tropical environment. My system runs year round). Down the road, I may decide to put it on its own zone and control it through the irrigation system. There’s a tradeoff there as my irrigation pump wouldn’t be moving much volume on a standalone zone, but I can probably engineer a bypass to deal with that.

4) statement : the irrigation pump becomes a pool pump at this point and needs to be bonded with everything else and GFCI'd.

That is an excellent point and something I had not gotten around to thinking about. The pump circuit is easy enough to GFCI. The bonding I’ll have to think on. Would it be possible to ground the pump locally with a suitable grounding rod and use earth as the common bond between the pool and the pump? Realistically, if the zone valve is closed, that rubber valve diaphragm is isolating the two sides of the circuit, is it not? Not that it’s not a valid point, just wondering how far down the rabbit hole I need to go here, practically speaking.

Otherwise, I wonder how big of a wire I would need to run between the two. You’re not really moving much in the way of current, as I understand it, so I would think a fairly small wire would suffice to accomplish the goal of bonding the two. If I drive a grounding rod down into the water table, I’d be able to use the water table as an electrical path too, wouldn’t I? This is not my expertise.

 

[Newdude]

My auto fill is just a toilet tank fill valve. I don’t know exactly how much evaporation loss I have each day, but I don’t think its enough to overwhelm the zone cycle time.

You evaporation is all over the place and some weeks needs nothing while others need many hours of runtime a day.

Score one vote for the traditional city water that's always on and you never need to step in and adjust run time.

If it is, I’ll just give it a dedicated zone

Better, because with a shared zone, you'll need lots more runtime and the poor flower bed will be mush.

But the dedicated zone will need to be watched to not dead head the pump when full. It will need babysitting.

Score two for city fill.
 

It will still only run with the pump, and you'll be adjusting the runtime to not burn out the pump.

There’s a tradeoff there as my irrigation pump wouldn’t be moving much volume on a standalone zone, but I can probably engineer a bypass to deal with that.

More fiddling and remembering to turn it all off. I had to always set timers to remember. It's own PITA. Lol.

The bonding I’ll have to think on

Hit up the Wiki in the left side bar or towards the bottom of any forum page. There's a couple of bonding/grounding entries covering it all. They are two totally different animals. A cow and a horse both have 4 legs and a tail. But.

 

[ol_whistle_britches]

You, sir, are dashing my hopes of being a unique and special pool owner snowflake. LOL!

I should just replace the autofill valve with an ultrasonic tank level sensor and a PLC… I’ll straight pipe the irrigation circuit over towards the pool at an upward 45 and let it arc into the pool like a water fountain when the sensor calls for fill.

 

[Newdude]

You, sir, are dashing my hopes of being a unique and special pool owner snowflake.

Just doing my part to make you really think it through. If it's appropriately weighed out and you still want to forget ahead, then there's less chance of regrets.

And then maybe more work/expene setting up filtering and UV for unpotable water.

If i have to go out and turn it on, and adjust it and then remember to check and turn it off......... why am I not just using a hose for the same effort ? It's no longer an autofill, It's a more complicated turn on the hose setup.

The city water/autofill is hands off.