YESSSSSSSSSS all seems successful , had to work this morning and had a go this afternoon , only problem was weight at first but once the water was in the pipes the drains seem to be holding position nicely , got to dark with the miserable day to take fotos but off work tommorow so see what we can do , as i had said previously we had a matrix system in the pond and when jen and i removed it it stirred up a fair amount of crud we attached a length of inch and a half pipe to each drain and married into the existing flexi , this also seems to stabilise the drain so it sits nicely on the bottom when full of water also adding without a doubt that little bit of extra weight ...so to finish off today all seems to be ok but more to report on the test run tommorow ...
andy ....perhaps someone who has converted to spindrifter\aerated lids and no longer needs there standard bottom drain lid, these two i used are kockney koi so i am pretty sure they can supply there must be somebody out there with a spare to help andy have a go at building one of these .........more to come
An idea for you in regards to weight if needed. You could make a ring by using large air hose and a straight conector. It comes in 25mm or 31mm. Fill it with sand and bond it to the under side of the dome, assuming their is space in there to do it and that it would not interfere with flow. That should add a nice bit of weight to it and keep it firmly on the bottom.