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I'm putting together two 8x4x12" beds (mostly as a final filter) and decided to try Stalite.

Just picked up the first load today and thought I'd post some picks and eventually any helpful information.  That's a quarter in the first two images.  Dry weight is about .78 ton per CY.

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Hi David,

I didn't see any updates regarding the Ph returning to more desirable levels. 

Did it? 

How long did it take??

Did you have to make other adjustments to achieve desired Ph after implementing the Stalite?

 

Just curious,  Thanks

 

Only 1/2 inch available here in Jax.  How much of a risk of clogging do you think I'd be taking?  I would think that 1/2 inch is as big as most river gravel.

TCLynx said:
Looking at the photos and the size of the pieces, if that was 3/4" I wouldn't go smaller.  3/4" looks just about perfect while 1/2" normally means more like 1/2" and smaller.

Teresa,

The pH is still high.  I'm not sure if its because I have a high algae content or if its a function of the stones.  The system has been active for quite a while now and I've probably cycled the water at least two times due to evaporation and over-flows.  I don't believe that I have enough fish in the system yet ( ~ 200, most < 4" ) to assist in dropping the pH.  I'm also running one full 32' raft bed just for duckweed.  I don't know what affect this may have on pH but I'm sure its consuming much of the available nutrients.  I should be increasing the fish count to 500 in the next month and a half so we'll see how that affects the numbers.  We've got tomatoes and melon doing well in gravel but struggling in rafts. Different types of leafy greens are growing but sporting a paler color than normal.  I made the mistake of letting lake algae get in the system.  I don't think it would be a big deal if I have all of the rafts down but at the moment we've only got part of two 32' raft beds covered.  I've actually considered draining, drying and cleaning one bed to see if that helps.
Teresa Schmidt said:

Hi David,

I didn't see any updates regarding the Ph returning to more desirable levels. 

Did it? 

How long did it take??

Did you have to make other adjustments to achieve desired Ph after implementing the Stalite?

 

Just curious,  Thanks

 

Stalite is PH neutral.

Teresa Schmidt said:

Hi David,

I didn't see any updates regarding the Ph returning to more desirable levels. 

Initially all the expanded products have a dust on them from the kiln process that can elevate the pH if it is not rinsed off before putting it into the system.

 

1/2" would probably be very similar to my river rock and will work if you can't get any larger.  Just be sure to have plenty of grow beds for the system stocking.

 

Algae, put something over the bed to block out the light and it will kill the algae.  Then if possible pump the dead algae water through your grow beds so the algae can decompose in the beds and provide a chemical that will inhibit future algae.  Water changes are generally not very effective long term against algae.

 

If the pH is staying up long term, I would suspect your source water.  If I'm using well water to top up my 300 gallon system the pH will stay up at 7.6 but if I use rain water to top up for a while the pH will drop below 6 and I have to add potassium bicarbonate and lime to buffer the pH up a bit.

Stalite may very well be pH neutral but the yard where I picked it up loaded it from the bottom.  I'm guessing that it was being stored near limestone or some other high pH material.  Even after strong washing small samples still read high.  My water reads pretty neutral.

Geoge said:
Stalite is PH neutral.

Teresa Schmidt said:

Hi David,

I didn't see any updates regarding the Ph returning to more desirable levels. 

The dust from the kiln process will temporarily boost pH in any of the expanded products (expanded clay, shale, slate etc.)

 

Just note that tap water may read pretty neutral when you first draw it from the tap.  Water in pipes, pressure tanks and out of wells has dissolved carbon dioxide trapped in it and that will act as a weak acid until it escapes.  If I test my well water right out of the tap, It reads about 7.  If I leave that water to aerate overnight and test the pH again it will be well over 8.  So, beware the false low pH of tap water right from the faucet.

Thanks.  I'll draw some and let it stand for a couple of hours then test it.  My pH has been in the 8 to 9 range consistently.



TCLynx said:

The dust from the kiln process will temporarily boost pH in any of the expanded products (expanded clay, shale, slate etc.)

 

Just note that tap water may read pretty neutral when you first draw it from the tap.  Water in pipes, pressure tanks and out of wells has dissolved carbon dioxide trapped in it and that will act as a weak acid until it escapes.  If I test my well water right out of the tap, It reads about 7.  If I leave that water to aerate overnight and test the pH again it will be well over 8.  So, beware the false low pH of tap water right from the faucet.

Continually elevated pH is generally either the fault of the media or the top up water.  If you rinsed the media well and there wern't chunks of limestone in it and your tanks are not made of concrete full of limestone aggregate, then that will lead me to suspect your top up water.  Are you on well water?  Now I know there are some wells in Florida that will get low pH water and there are other wells here that will give you a version of liquid limestone.  My well gives me water that after airing out has a pH between 8-8.4 depending on time of year and how bad the drought is.

David,

It has been a few months and I am wondering how your expanded shale grow beds are doing?  Would you use it again?

I am getting ready to start a tote size system and wondering if shale is the way to go.  Any advice??

 

Big David in Miami, Florida

 

Not that you asked me but since you are in Miami and therefore have access to 3/4 inch, I can't think of a reason not to use it.  It's light and has a large surface area so I don't know of a better biological filter material for the price and there are no issues with PH, other than possibly at start up, when your PH is likely to be high (in Miami) regardless of the material you choose. 

Good luck with your system

In miami, since you have access to a good price on 3/4" stalite, just get a jug of muratic acid and after you do your initial rinse of the stalite and put it in the bed, do an acid wash with like 1 cup of acid with 100 gallons of hard well water to help mitigate the alkali start up of the stalite.  Be sure to rinse the initial acid water to waste before hooking up to the system.

And you still need to do the extra labor of rinsing the media before putting it in the system.

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