RubyCreekTed, Welcome to the forum!

I put about 5 gal of pond water in my sprayer then dumped the 50lb bag of alum in and mixed it pretty well by swirling my hand around in the sprayer and then continue to fill the sprayer with pond water while mixing (watch your arm on the sprayer opening edge, it can be sharp!). Not all of it will dissolve in the 35 gallons, but I refill the sprayer with pond water when it is half full and continue spraying. The alum WILL get hot if it clumps up badly, but not enough to burn. No chemical burn danger either, the acidic PH is like vinegar. I doubt you will get much improvement with 25lbs unless your pond is about 2 feet deep. 150lbs would be closer to enough.

If you don't get ALL the suspended clay out, the positive charge effect from the alum will be quickly neutralized and the clay will re-suspend as fish swim along the bottom and stir it back up. It is virtually impossible to over treat the pond and the extra alum is very good insurance. Also, unless your ph is around 8, add hydrated lime at 1/2 the weight of the alum to be sure to avoid too much drop in ph. The ph drop is WAY over rated as for danger though, the warnings are more of a legal CYA for the advisors.

Alum has been in my spayer for 3 years without clogging. The last use was to clear N&Cponds, pond about 2 months ago. I'm sure your sprayer is made by Fimco, It sounds exactly like mine. 30 foot spray spread? I adjusted my nozzles to spay about 5-8 feet wide and just circled the pond gradually getting tighter and concentrated the most spray in the deeper parts of the pond. If you use enough alum, the pond will be cleared completely in under 24 hours. If it takes longer, not enough alum has been used. I have read that alum, applied properly and not flushed out , will be effective for up to 15 years. If you get it ALL settled quickly though, it should never be a problem again, unless you have clay continuing to run into the pond. For runoff, you will need a grass buffer strip.

Best of luck and be sure to take before and after pics to post!

PS
I sent you a PM (private message), Check the "My Stuff" header at the top of the thread.