So how did you get hooked.

[Ira]

So, we all have a bunch of in vitro fish?

[Pegasus]

Hi Hobbit,

IMHO those that that use U/G filters and complain that it robs their plants of nutrients have either too little depth of substrate in their tanks, (eg, min 75mm - 100mm sloping to the rear) or they didn't prepare the area that they wanted to plant strong rooted plants.

By this I mean that the simple answer is to place a disc of plastic (cut from an ice cream container) directly over the U/G filter in the area the strong rooted plant will occupy.

This will stop any excessive drawing of nutrients from being drawn away from the roots beneath the substrate.

I am at the moment running two U/G filters with 15mm uplifts that are probably lifting 100 plus litres an hour, and all my plants are growing by "visual amounts" each day, and I have no discs over the filter plates.

I am also running a waterfall system that is homemade and is churning out a similar amount per hour.

As far as cleaning is concerned, I can honestly say that I have never had to strip a tank in order to clean the U/G filter.

Simply push a small hose down the uptake tube... create a syphon.. eg, suck on it... and any excessive crap will be drawn from beneath the plates without disruption to the bio system.

Substrate is the answer to good U/G filtration, eg, the right amount, the right size.

Too big and everything gets sucked through too easily, plus food gets trapped between the large particles.... Too small and the filter cannot draw the solid wastes gradually through the substrate.

Bill (Pegasus)

[darylh]

Siphoning crap from under a UG ... don't just stick a hose down the uplift and suck.

Fill the siphon hose with water and stick it down the uplift (much easier if there are two uplifts) but don't let it draw water off yet. Stop air from escaping so that under the plate fills up with air. When your pump can no longer stand the strain or bubbles start to escape from some point in the gravel ... let it all go, siphon and air.

Water rushes back through the gravel and stirs up all the muck ... you'll be amazed at how much more you get out of there.

It's child's play with two uplifts. But if you muck it up and fill your tank with all that gunk, don't blame me ... get a gravel cleaner.

PS: don't put that stuff down the drain ... the vege garden loves it ... you'll have tomatoes the size of watermelons