Pump question (not a shower pump!)

Sounds like a magnetically coupled pump (magpump) with a sealed impellor housing. March May make a range of these pumps. I aven't found a web address but this is their number - 01480) 214444 - they are in St Neots. The most regular failure of these pumps is caused through running them dry, this melts the seating of the impellor bearing.

Central heating circulators (pumps to you & me) will take all sorts of abuse and are free for the skipdiving.

Mind you what sort of 'acid' is he feeding his 'tomato plants' ? ;-)

Do they have an isolated impeller John? I'n not sure how the seals / bearings would cope in this environment?

I'm not exactly sure .. other than whatever it is, it's safe enough to put yer fingers in (apparently)?

The plants need a ph of 5.5 (or summat) and as the water is regularly pumped round to each plant from a tank the size of a swimming pool, it's 'mixed' (on the fly) in a small tank (the size of a domestic water tank) with acid / alkali to try to hit the required ph.

He even buys boxes of bees in to assist with the pollenation .. 1 pound 50 per bee I believe!

All the best ..

T i m

The last set up I saw was under the trade name VOCOM. IIRC there were storage tanks for about three lots of feedstock and a buffer tank which recirculated via a pump with graduated injector valves which were located on the suction side of the pump so as to draw the stock chemicals into the water. I can recall pH probes, conductivity, and dissolved oxygen probes in the control loop as well as a flow sensor in the pumped output to the greenhouses which gave early indication to the programmable controller handling everything. Out in the greenhouses the header pipe branched off via solenoid valves to subsections of the crop. It was possible to give each section a session of "watering" with appropriate nutrients for that particular crop. The pumps on a Vocom were Grundfos again IIRC

Phosphoric sticks in my mind so probably weak Coca Cola strength

Cucumber growers use biological predators to control aphids and other pests (but don't ask about the Hydroflouric acid used each year to clean the glass or the formaldehyde sprayed about with gay abandon to clean up during the off season)