My TA is 250 following a fresh fill and I am planning to lower it with the acid/aeration method. I went to Lowes today to get some PVC to attach to one of my return eyes ... and had a question ...

Rather than trying to "splash" the water coming into the pool, why not just open the pump intake on the filter basket a bit to allow air to come in? It would get mixed by the pump way more than any air dropped or slashed by my pvc solutions.... so what am I missing here?

If I can find a level of air induction into the pump that doesn't lose prime, wouldn't that effectively aerate more thoroughly than splashing?

That is a fair enough question and one that I have not heard addressed before. I am interested in hearing the responses to this one.

It's not a good idea to deliberately cause an air leak on the suction side. You could lose prime and damage your pump. Also, the air entrainment cavitation* is not good for the pump/filter.

*In this case, cavitation is used in the broader sense of holes, or "cavities", in the water vs. cavitation caused by very low pressure causing the water to vaporize.

I'd say go ahead and hook up the aerator like you were planning. I think you'll be amazed how much frothing it'll generate! I'd bet it's more than you could possibly introduce by loosening the pump lid, plus there's no risk of damage to anything.

I currently run Ozone into the suction side -- which introduces a certain degree of aeration (presumably controlable and safe) so this is a question of increasing that inflow to a maximum "Safe" level of air intake ....

I certainly wasn't going to "loosen the pump lid" ...

And no doubt I can make a lot of frothing with the return ...

But direct injection has been proven to be better than splash even when splash looked good ... why not directly inject into the pump where the pump can use it to scrub the CO2?

Air ingestion in a centrifugal pump is not good. Centrifugal pumps are not designed to handle air bubbles in the fluid. They will generally tolerate only 0.5 % by volume. At 2 % air by volume, the pump might lose 10 % of performance and at 4 % air by volume, the performance loss can exceed 40 %. Depending on the pump design, the pump will lose prime at around 6 to 10 % air by volume.

Air, or other gasses, should never be introduced into the suction of a centrifugal pump. Entrained air/gasses will cause a significant loss of efficiency and performance. It can cause vibration, noise, erosion of metal components, turbulence, impeller damage and other problems.

Not to beat a dead horse ...

It's a self-priming pump and I don't intend to run it that way for more than the time necessary to lower ph ...

So, there seems to be really a couple questions here ... One is about the efficacy/efficiency of using the pump to churn and aerate the water, and the second regarding the practical ramification on the the motor.

It is probably easier and certainly runs much less risk to the equipment to setup a fountain on one of the returns, perhaps something like this one. What you describe could work, but it also runs a noticeable risk of damaging the pump if something goes wrong. In this case, there is absolutely no reason to run that risk.

Also, note that you really don't have to aerate. The carbon dioxide will naturally off-gas anyway. Aeration just speeds up the process.

What is your calcium level?

Built this:

That'll do just fine

What is the coping, is it a sandstone?

Yeah -- and its dirty from all the clean-up efforts from after the fire. My pool was a TOTAL mess a few days ago from wildfires we experienced on the 4th of Last month.