Heat retention in grow bed media

[txdurk]

I live in Houston, Texas and it gets a bit warm down here in summer. We call them 95-95 days for 95F and 95% humidity but it isn't unheard of to go over 100F. I am planning a system and was concerned with the grow bed media retaining solar heat and the negative affects it would have on my plants and fish. My fish tanks can be shaded from the sun and half buried in the ground to capture some cooling effect but the grow beds will be in the SE texas sun all day. The media types I am considering using are shale, hydroton, or pea gravel. I have shale and pea gravel readily available locally. I'd have to ship in hydroton I believe. Ideally, I think the one that retains the least heat wins out. In worst case I could also place shade cloth over the grow beds or slatted wood but I may be limiting sunshine and it adds cost.

Maybe the evaporative effect of the water in the grow beds will cool everything down a bit. I just don't have first hand experience with it yet. Any advice or experiences from other hot weather APers would be appreciated.

[Chip Pilkington]

One additional thought - if you go with a river rock type media, you often have lighter color options available. Just don't forget to test it.

A light GB color could help if you are concerned.

The larger your total system capacity, the more stable your temps. Your idea about burying tank and/or sump is a great year 'round stabilizer.

[txdurk]

@Chip: Thank you for pointing out the gravel color variable to me. I'm not sure I would have thought about that on my own but it could make all the difference. Rgds.

[Chip Pilkington]

Hi Dave,

No worries, got to take advantage of everything you can when you live in challenging environments, right?

Hey, being in Houston area, do you get to the ocean much? I previously mentioned river rock, but the stuff I'm using now is actually from the ocean. Has a few small shells in the mix, but overall it works well. Still have to test it though. Mine passes the vinegar test, but I do wonder if the shells do a little buffering...

In the past, I've brought two sizes of screen, a few buckets and sifted it myself for proper size. It's a little bit of work but I like the DIY thing. My rock runs between 5/8" and 3/4" and works well.

[txdurk]

@Chip: My house is 80 miles from Galveston and the Gulf of Mexico. I usually get down there at least once a year. I've never been impressed withe the the Gulf though. Shrimp boats and shoal waters churn up the bottom leaving the water a brownish-green. I much prefer the look of either of the two oceans, Thanks for the assistance. Rgds.

[TCLynx]

Very minimal amounts of shells are ok, I'm sure they do a little buffering for you but as long as they are minimal.  I had about 40% of my media as shells at one time.  That was NO GOOD.  My 300 gallon system is all Quartz type river rock and I can get the pH down in the mid 6 range on that and actually get to buffer up with some potassium bicarbonate (this is actually and exciting good thing to me.)  Now I'm replacing my shell mixed media in the big system with an expanded product.

[Chip Pilkington]

Hi TC,
Actually, the last thing I need is buffering. I consistently run close to 8 on all systems, regardless of media. Plants and fish do fine, but I use rainwater for top ups, which helps a little. I top up a good 10% or more every week, unless the rain does it for me. After a good rain or two I will find it in the low 7's - I'd be thrilled if I could maintain pH 7. But I refuse to chase pH up and down with chemicals. I've seen (on these forums) way too many problems from quick reactions to high pH, particularly on systems not fully matured.

[TCLynx]

I agree Chip, my well water is hard and I wish it would rain more for me as I can actually get a pH down below 6.5 if I'm not constantly topping up with well water.