Substrate Media

Hey guys, I have read that white pool filter sand is a great looking substrate.

Has anyone here ever used it, and is it safe?

There is close to 50 posts on the subject...

let me dig up some links

http://www.discusforums.com/forum/viewtopic.php?t=2969

http://www.discusforums.com/forum/viewtopic.php?t=934

Quoted from one of the other threads:

Quote:

Originally Posted by Mud Crab

Being a geologist, I know quiet a bit of info about sands etc. Just some pointers to take into consideration:
1) If the sand is poorly sorted (large and small grains), You probs need two seives. One size is to get rid of the large stuff and the next size down is to keep the good stuff and throw away the finer stuff which would go through the second seive.
2) Black rocks (sedimentary or igneous) tend to have sulphur in various concentrations.
3) Steer away from rocks that are derived from granites. These tend to increase the CaCO3 due to plagioclase (the white stuff) having this stuff.
4) Try to get the sand from as far away from the source as possible as most of the soluble minerals would have disolved by then.
5) The best option is find a stream/creek that basically has nearly 100% quartz content in it. These are found generally near river mouths or on alluvial plains which generally pass through the suburbs anyway.
6) Get yourself a handlense or magnifying glass so that you can identify the percentage of quartz in a handsample. Over 80% quartz is good.
...hope this sorta helps. I didnt want to get too much involved.

Oh, forgot to mention that when using a handlense, determine the sphericity (roundness) of most the grains. Well rounded grains aint too good for porosity and permeability (circulation) within the substrate.

Quote:

("...most washed river sand are a quartz based product here in OZ..."). Anywhere there is a hill, mountain or exposed bedrock with a creek or similar passing through it you will get more than quartz in your creek sand that it is eroded from . Also dependant factors influencing the outcome as to the type of sand in a creek is the mechanism of erosion experienced at the source (physical/ chemical and/or mechanical weathering). Without going into too much detail, it is true that the Australian geology exposed at the surface is generally older than most parts of the world and more weathered. We have the some of the oldest soils in the world which consist of aluminium rich laterites. Dependant on location then within Australia, you will find more quartz in a creek than others, with some creeks based entirley on quartz due to erosion probably of the soil profile, or other factors mentioned previuosly. For the sake of those in Sydney, a relatively good chance of finding good quartz beds is steer away from the hills and focus more on any creeks that cut through the plains and especially cut through previuosly deposited alluvium and old soil beds where no bedrock is exposed. Also, if the hills are composed of quartzite (sandstone) you have good bet of close to 100% quartz sands in creeks that flow away from them. Even a quick phone call to the geology department in any university will find more than helpful staff who will go out of their way to help you. Ask them where you can find quartz rich, well sorted creek beds or even the location of old sand dunes preserved as hills which will have a mix of soil and quartz. If you are after a particular look or colour of rock, sand...they can help you on that point to. It is the geologists responsiblity to know their local area and believe me, they know where to find the best sand and display rocks which will cost you only time and petrol and an outing with kids. For those of us in northern Australia, it is much more difficult as the creeks/rivers up here have fast flow rates, which means that pebbles are further deposited downstream than they are down south and weathered within the creeks reducing quartz percentages.

Quote:

Just a pointer about sand raising pH. Sand is a general term used to describe the size of a weathered rock and generally also contains an accumulation of minerals that contain by nature an assortment of elements...Calcium, Iron, Sulphur, etc.. If you are certain that the sand is derived from the weathering of a quartzite bed further upstream then no chemical alteration of your water will take place. Silicon is relatively insoluble in water and it this element that makes up quartz alone. A simple handlense will show you if you have quartz or some other stuff you dont want. Quartz can be identified by the way it fractures. Geologists use this property in identifying quartz at it has no cleavage but breaks and leaves what we call a "conchoidal fracture":which looks like a broken beer bottle. If you see flat shiny surfaces it aint quartz even though it may look like it. This stuff may alter your water chemistry. If the grains are too rounded when you look at them, break them on a flat surface with a hammer and then have another look.

http://www.discusforums.com/forum/fi...9__medium_.jpg

Quote:

Well, I couldnt resist....nice pic of sand. I was able to define well sorted and angular clasts of 90% at most quartz. I would side on 85% to be safe Judging by the iron staining on some grains, I would say the black stuff is basalt (iron and magnesium) with some independant grains of white coloured, rounded clasts of feldspars-plagioclase (calcium + potassium?). Its worth the note that the soluble minerals are rounded in this pic...makes me excited to see the difference There are some other unknowns which have have assorted colours and is probably just filling used by the company to dilute quartz content and thus save $$$ All in all, a relatively safe mix with minimal alteration of water chemistry should be enjoyed by this sample. Good porosity and permeability of water and nutrient flow should be enjoyed by this sand with minimal compaction due to the "locking" effect of angular grains in contact with adjacent grains. Hope this helps

Thanks a lot Proteus.

Sorry, I should have searched harder, but I actaully read about this off a reef forum and didnt think it would be popular in the Discus community.

How about beach sand?

(I know its illegal)

too salty (until washed)

too dirty

pathogens

pool filter sand comes prebagged for your convenience :wink:

Thanks for the reply.

You wouldnt happen to know the particular brand of this filter sand would you?

All I have seen at the local pool shop is Zeolite, but I have read that it is not inert.

yeah you don't want zeolite

just a simple quartz fine sand

thats all :wink: