By the way with the negative edge if you and hubby had to do it over again is there anything you would change or advise
Of course! Isn't there always?
When we built our pond, we followed instructions for a rain exchange under the negative edge because essentially that was what we were doing. But some things definitely don't work when it's a pond flowing into the gravel vs just recirculating clean rain water, which is the model we were following. For example, the recommendation was to put a layer of landscape fabric over the top of the aquablox and then add large rocks, then another layer of fabric, then smaller rocks, then another fabric, then large gravel, then MORE fabric and finally pea gravel. Well, all that fabric clogged up within a matter of days.
We ended up cutting out as much fabric as we could, which of course meant the various sized rocks and gravel got mixed, which lead to complete gridlock. We spent a year trying to find a good solution for keeping it free of debris, including using a power washer. We finally took all the gravel and rock out (and by "we" I mean one of my sons!), got out all the fabric, laid a base layer of small sized boulders and then covered that with golf ball sized rock. Now it works great. We still have to clean it, but the boulders never move and the all-one-sized rocks are easy to clean and shift around with a rake.
And while we do have an overflow in our rain exchange, we would have increased the size. I think it's a 3 inch pipe. It could drain a bit faster when we get heavy rain.
Knowing what we know now we may have just gone with an intake bay instead of the negative edge. I haven't done much research on those though, but the idea intrigues me.
