Vickie,

You know how most fertilizers have nitrogen/phos/potas (N/P/K)? It's primarily the phos that you don't ever want in the water, along with EXCESSIVE amts of the other two.

I wouldn't recommend the tabs in the gravel with mesh pots. Even if you don't have fertilizers with phos in them you can't really control the amts of nit & potas getting into the water.

So long as you don't use excessive amounts of fertilizer at one time there should not be a problem. Simply continue to use your test kit. If you are still concerned use the fertilizer half strength and add it twice as often.

I use Jobs Tomatoe spikes in my plant baskets that are mesh and are filled with pea gravel. I have no algae in my pond at all.

I know that Drh1 posted about his use of potassium nitrate (some liquid stump removers) on the site. I think it might be in FAQ on the start page.

I've used it with great success last year -- the water hyac really took off over the previous year. Since you're talking about bare roots getting fertilized water, I would think that this would be a more controlled method of delivering it in a pond. (I think his rate was about 1 tspn per week to about 1500 - 2000 gals... but check his record/posts.

You are all a wealth of information, thank you.