Bob Hart's 4" isolators

[estanque_koi]

In an old thread Bob Hart featured some DIY isolators that he used instead of valves:
http://www.koiquest.co.uk/forum/viewtopic.p ... &sk=t&sd=a" onclick="window.open(this.href);return false;
Quote: "So rather than spend £200-£250 on 3 4" ball valves, I made up some 4" isolators from 2" pipe and some rubber toilet pan connectors. These act like the unit used to isolate the middle outlet pipe on Nexus units"

Bob, are you happy with these isolators, are they reliable and doing their work properly?

[Bob Hart]

Hi Diego,

It seemed a long time ago I made those up, but the tread says only just over a year. One of them is still actually in place as I havent got that bottom drain working yet, so they will hold the water back easily.

To use as a daily/weekly isolation 'valve' though, I have found 2 issues, as follows:
1. When inserted it fits in nice and easy. To remove though, what is happenning is that the rubber ridged part is being asked to trun 180 degrees. When inserted the ridges lay flat inside the pipe and removing it is difficult. It needs to be well 'greased' and a bit of brute force to twist the pipe and pull. This could be accomplished better with a 'T' piece on the top of the pipe.
2. The rifged rubber came off a few times. Fixed it will cable ties and a couple of screws through the rubber into the pipe.

What I have ended up using is slide valves. These dont fully hold water though (do they ever!), but are adequate fro waht I need. Should the slide valve ever need replacing though, I can insert my 'pipes' back through the top of the 'T' and isolate the bottom drain.

I have also used these 'pipes' for removing a large Vortex which was connected to 2 bottom drains. A quick bit of water loss and the 'pipe' was fitted, which then allowed the 4" bottom drain upstand to be cut to the correct length and a 'T' fitted. Then onto sieve's fitted and all without draining the pond at all.

So all in all a useful tool, but I dont use it daily to isolate.

[estanque_koi]

Thanks for the info, Bob