i have a strange problem

[joegrow22]

Hey guys,
so i am growing some plants in waterfarm buckets. One of my plant's growth has slowed down a bit, it still is healhy, and there is nothing wrong wih my leaves. The plant is in coca balls, and one of them is really flimsy. It falls down easily. The stem is like 1 inch thick (in diameter) so it is really weird that its happening.
Also, when i check my pH of my res in the bucket, it often goes down over time instead of up, which is strange and i don't know why. The plant was started in a rapid rooter, and i have tried to put the rapid rooter down farther, but it hasn't really been helping. Would this problem have anything to do with the roots ? And is this problem u think connected in any way to the pH going down instead of up? What would cause the pH to go down?

 

[Growdude]

I use waterfarms but I use hydroton as the medium and plants never fall over.
When your PH is falling your PPM is probably riseing, do you have a ppm meter?
Its caused by excessive salt build up.

 

[Bubby]

^Which means you should change the water.

 

[clever_intuition]

^Which means you should change the water.

And be sure to use distilled or rain water when doing so