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Using Oil-Dri for cheap substrate?

24K views 107 replies 31 participants last post by  Mizuhuman 
#1 ·
I am going to set up a couple very low-tech 10 gallons in my basement to hold some extra plants and I was looking for a cheap substrate. I want to try something different though for these tanks. I have heard that kitty litter works well, but is there a difference between that and Oil-Dri?

I also need to add some to my emersed tank so it is not just mud sitting in the open.
 
#2 ·
The best of the Oil Dri sorts of products is Safe T Sorb. So far I have only found it available at Tractor Supply.

Kitty Litter may work for some, but different kinds may fall apart, cloud the water and so on.

The Oil Dri products are better, do some more research. Many are white or off white. That is not much of an issue in a grow out tank, but if you move those plants to a tank with different substrate and some of the Oil Dri sticks to the roots the whiter material of most Oil Dri products would not work too well.

Safe T Sorb seems the best of them all. Pretty good color too.

A related material is used in sports fields, and may be cheaper if you are not near a Tractor Supply. For me it is about twice the price, but the saving in gas makes it half the price of going to Tractor Supply. It is sold at irrigation stores like Ewing or John Deere. It is called Turface Pro League. It comes in several colors. The redder one is too red, but the other colors are fairly subtle. I started using Soil Master Select, Charcoal and it works pretty well, and I like the color. Unfortunately SMS is not available any more. Turface is about the same, though.

All of these materials are relatively lightweight, so some plants might need a rock on them to hold them down until they root.
They are all high cationic exchange capacity.
Turface and SMS will remove the carbonates from the water. I have stopped that with coral sand, mixing something like 50% Turface with 50% coral sand. I use that for a Lake Tanganyika tank. You could also mix in oyster shell grit (sold for caged birds like Budgies) or limestone sand or very fine gravel.
 
#5 ·
[snipped] .......
Turface and SMS will remove the carbonates from the water. I have stopped that with coral sand, mixing something like 50% Turface with 50% coral sand. I use that for a Lake Tanganyika tank. You could also mix in oyster shell grit (sold for caged birds like Budgies) or limestone sand or very fine gravel.
I'm getting ready to change the substrate in my 75 gal to the Safe-T-Sorb which I think will remove carbonates also. ??? I thought I read soaking it first would help that problem ... does it? I soaked it for several weeks.

I had already bought some oyster shell grit in anticipation but now thinking if the soaking doesn't help much that it's no where near enough since you're using 50/50 mix Turface/coral sand. I wasn't planning on mixing it but rather putting it in my filters. Is that even going to work as it sounds like it requires way more than I'll have room for. I've got a test kit coming but right now have no idea what my kh or gh is. So I guess I'll just have to wait for the kit, do some testing and go from there.
 
#7 ·
Yep. It's the real deal, I used this same bag in my 25g and have a ton left over. It's WAY less dusty than oil dri and looks much better.

The carbonate absorption goes away after a little while, but it depends on how much you use. Personally, I use gh booster every water change so it's not a big deal
 
#8 ·
Carbonate and GH is not the same.

I have used SMS and Turface that remove KH but leave the GH alone. I assume the other clays will behave similarly, but an actual test run is the only way to know for sure.

I have coral sand and oyster shell grit in the filters of some tanks, and it is not enough to offset the removal of carbonates by the SMS.

Soaking in liquid rock might help. So much carbonates the material gets saturated. Cannot remove any more from the water. That eventually happened with some of the SMS that I kept adding baking soda to.

Safe T Sorb ordered!
 
#12 ·
@ diana .. what is liquid rock?

I really should have "pre-charged" the STS when I was soaking it but the long soak wasn't really intentional. Just had too many other things going on to deal with it. And I was using the copious amounts of rainfall to help clean it.

So hopefully between the oyster shell grit and baking soda I keep the Kh up. Guess I'll find out.
 
#15 ·
Tank is set up with Safe-T-Sorb. The substrate looks just like Roy's picture! I am still working out the 'scape. 40 lb bag did a tank 5' x 16", 2" deep. I actually have it sloped, only about 1" in the front, 3" in the back. I doubt it will stay, though.

I dumped it into the tank dry (very careful not to breathe the dust) then filled the tank about 6" with a strong flow from the hose, making sure to stir the material as much as I could. Water was pretty muddy looking. Pumped that out. Second filling (again, 6" deep, lots of stirring) still somewhat muddy, but better.
Next filling was running the water in slowly over the (empty) STS bag. The filled tank has some haze to it, but I would go ahead and put fish in it, it is not that bad. However, I am doing a fishless cycle while I continue 'scaping, so fish are a little while off.
I will also monitor the KH, and report back.
 
#17 ·
I suppose you could make some liquid rock!
Since these materials remove the KH, you could make some high KH water to soak the substrate in, see if it would reduce the problems with KH being removed later, when things are set up.

I suppose you could also add fertilizers. With a high cationic exchange capacity you could pre-load the substrate.

STS in the 88 gallon tank is still looking good, the water is a lot clearer. (I am running 2 canister filters on it).
 
#18 ·
The rinsed STS has been sitting in my 18 gallon totes for so long now it's probably dry again. LOL Yeah I should have pre-loaded it. May still do it yet. I seem to keep putting off changing the substrate out since it seems like it's going to be a big job and would prefer to have it some on 1 day.

So it only took you 1-40lb bag to do an 88 gal tank. I bought 2 thinking I would need more than 1 bag for my 75 gal. I guess I'll have plenty. :)

I added several handfuls to my almost full of water tank a while back right before my bluegill started making his nest just to see how much of a mess it would make with all his tail fanning ... wasn't bad at all. And what little he did stir up settled quickly with almost no clouding of the water. Of course that was just 1 little area and it did get mixed into the gravel, but was happy enough with it's performance to do the whole tank. Someday soon I'll get around to that. :icon_lol:
 
#19 ·
Yes, the 40 lb was barely enough. 5' x 16", and the substrate would be barely 2" if it was flat.

Tank is quite clear, now.

Ammonia is disappearing, but I think it is the plants. No nitrite yet. Nitrate is about consistent with the fertilizer dosing, or maybe a bit higher. I have not added much in the way of nitrifying bacteria. Just what was on the plants. The plants came out of tanks with very small bio load, so very few bacteria came with them.

KH is still as high as the tap water that I filled the tank with.
 
#20 ·
I won't be sloping front to back but may have some small mounds and valleys. Figured I'd have 4" in some spots while others may have only 2". I calculated for 3" if it was flat across the tank so bought an extra bag. I sure didn't want to run out while in the middle of re-doing the tank. Don't think the fishy's would like that. It's going to be stressful enough for them as it is. Plus I can always use the extra in another tank.

Keeps us informed how the KH does if you don't mind.
 
#21 ·
Something odd going on... the KH is rising.
Uh-oh... I used some pond fertilizer tablets that were in poor shape- more like powder to granules, not tablets any more. Dusted it on the bottom, under the substrate.

Fishless cycle chugging right along. Ammonia and nitrite readings high enough to grow plenty of bacteria.
Nitrate, too, but I add fertilizer for the plants, a blend that includes N. (plus the pond ferts!)

I may have over done the ferts. Gotta move more plants into the tank.
 
#23 ·
All I used was the Safe-T-Sorb, 40 pound bag.
The only additive was the pond fertilizer tablets, and they were pretty beat up. The granules went under the substrate.

The filters have an assortment of sponges, floss and ceramic bio-noodles. No chemical media.

Since then I have been adding ammonia for the bacteria, and fertilizers (macros and micros) for the plants.
KNO3
KH2PO4
K2SO4
CSM+B
Chelated Iron
Excel

The bacteria are removing about 1 ppm ammonia each day, so I add enough to bring it up to 3 ppm, about every other day. It got down to 1 ppm this evening. Nitrite is high. (I have a hard time telling the difference in the colors on the strips, and my API NO2 test is so old it no longer reacts)

KH is coming back down, and the pH is a bit lower. I think there was something in the fertilizer tablets. But what is making the KH drop so fast? The bacteria can't be growing THAT fast! They do use carbonates, but this is way more of a drop than that!
 
#24 ·
The sts sucks carbonates out of the water like a vacuum. This will continue for quite a while since you used 40 lbs. My suggestion is to buffer it quite high each water change to let the sts charge itself quicker. I used only a cap of it, and it still took a few weeks to stop
 
#25 ·
Yup, I bet the STS is taking over and removing KH. KH is totally crashed and pH is at the bottom of the chart. Added 2 tablespoons baking soda; this ought to raise the KH by about 4 German degrees of hardness, and bring the pH up a bit.

I added a lot of rock as a background, stirring the substrate some. It clouded up while I was working, then settled down really fast. This is a very good substrate, that way. It has not even been an hour since I was up to my shoulders moving rocks around, and the water has only a slight haze remaining.
 
#29 · (Edited)
Yup, I bet the STS is taking over and removing KH. KH is totally crashed and pH is at the bottom of the chart. Added 2 tablespoons baking soda; this ought to raise the KH by about 4 German degrees of hardness, and bring the pH up a bit.
Hi Diana,

I realize that baking soda will raise the dKH, and I use an online calculator to determine the amount of baking soda to add to accomplish the desired change.

How were you able to determine the dGH (General / German) change that would occur by adding the two tablespoons of baking soda?
 
#27 ·
I just converted a 10gal to sts and am really likeing it. It dropped the kh from about 14 to 8 and ph went down from 8.2 to 7.6 so it really does pull in the minerals.

I'm wondering if it would work to take some fresh dry sts and "load" it using ferts? Basically take some RO/DI water and dissolve whatverer micros and macros into it. Then add the sts for a week or so, rinse and use.
 
#30 ·
Roy, I have done this before with Soil Master Select. The first time was in a 29 gallon tank, KH and pH bottom of the test (KH=0, pH =6 or lower).
Add 1 teaspoon baking soda, let it circulate. Test. KH =2 German degrees of hardness, pH = 6.2. Repeated several times on 2 tanks the same size, then later similar results with other tanks ranging from 10 gallons to 125 gallons.

So... 1 teaspoon in a 29 (Done over several years, many tanks) = 2 degrees
so... 2 tablespoons in a 88 (The tank under discussion today) = 4 degrees

There are 3 teaspoons in a tablespoon, so I added 6 times as much to a tank that is 3 times as large, so the KH change ought to be twice as much.

It was late yesterday when I added the baking soda, so I did not go check it after it had circulated, and by now the substrate has probably removed it. I will post the test results later, and what I do about it.

I also have pH test strips that came from a lab, and test lower than the aquarium tests, so I will use those. They are probably more accurate, too.
KH test is API and Jungle test strips. I can use double the water sample in the API test to fine tune the numbers. No, the tests are not calibrated. While I am willing to pretend that I have results down into decimal places, I know it is not that accurate.

I am looking at the big picture:
This substrate removes pretty much all the carbonates from the water.
This allows the pH to drop way too low for the nitrifying bacteria to reproduce. (I am running the fishless cycle on this tank, remember)
So I want to fix it.
This would mean raising the KH to at least 3 degrees, and probably higher. (The original work identifying the correct species of nitrifying bacteria used a KH of about 8-9 German degrees of hardness, if I remember).

starquest, I think that is a good idea. These products have a high cationic exchange capacity, and will indeed soak up a lot of fertilizer. When I was using Soil Master Select and the EI method of fertilizing I think I got that substrate really well saturated with fertilizers. When I stopped dosing the tanks for a while the plants continued to do well for a couple of months. I would be leery of using too much fertilizer, though. You would not want so much that it would leach out into the tank water. I understand what a dry start is, but the root zone is wet, and too much fertilizer in the root zone may not be good. So, soak the substrate in fertilizer rich water, then drain away that water and refill with ordinary water (RO, tap or whatever- not enriched with fertilizer).

On the schedule for today: Water change. The ammonia removing bacteria are growing like crazy and have spiked the NO2 too high. I am not sure about the NO2 removing bacteria. It is too soon for them to really be growing that well, but the NO3 is high, too. I am thinking some of the NO3 reading is from fertilizer, and some from the bacteria.
I will test tap and tank before and after. (Garden plants are going to love this water!)

Water company adds sodium hydroxide to raise the pH. I suppose that is another item removed by the substrate, or else why would the pH drop so much? Normally the tap water is KH 4-5 degrees and pH high 7s, occasionally low 8s.
 
#31 ·
Seems like a lot work to keep the parameters balanced. Wouldn't buy any expensive fish until you get the parameters balanced. If you get tired of it you could take most of it out and add river sand without taking all of the water out.

I got a 50lb bag of river sand from landscaping co for $3.
 
#32 ·
So I'm assuming from the conversation that "pre-loading" the STS with ferts would help keep it from sucking up all the carbonates??

Any guidance on what ferts and how much to use for say 40 lb's. I actually have 80 lb but it's in 2 separate tubs waiting for me to put in my tank. Might as well load it up while it's just sitting there.
 
#33 ·
All right, here are today's results:

Recap: Tank was started Aug 30.
88 gallon tank with Safe-T-Sorb (1 bag, 40 lbs) as substrate.
Large flat rocks (neutral with respect to GH, KH, pH or TDS changes) have been installed across the back of the tank. This has taken up some of the water volume. I will take a wild guess and say maybe 5 gallons? Maybe a bit more. I am going to use 8 gallons, just to make the math easier.

Initial fill was done this way:
STS dumped in dry.
Tank filled to about 6" with lots of stirring, then siphoned out.
Refilled the same, and again siphoned out. At that point I moved the substrate around and put some old pond tablets under it. The 'tablets' were falling apart and more more like sand-sized particles.
3rd fill was to the top of the tank.
Tap water, dechlor.
I started adding ammonia, testing and adding until I had 5 ppm. Perhaps a bit more.
I also dosed macros (KNO3, KH2PO4, K2SO4)
Plants include 1 Anubias, some Valisneria, Hornwort, Water Lettuce, Duckweed and Azolla.
Filters are 2 Fluval 404 canisters. with sponges, floss and bio media. They were used, but dry, I assume all the bacteria was dead. I thought there were no chemical media in there, but today I cleaned them and found 1 nylon stocking with some coral sand, perhaps 1/2 cup, and 2 stockings of peat moss, perhaps 1-1/2 cup total.

Next day I tested the KH. Way high. I assumed it was the pond tablets. Ammonia showing, and a trace of nitrite and nitrate. I assumed these last 2 were from the fertilizer, not nitrifying bacteria.

Over the following week I kept track of the ammonia, nitrite and nitrate to monitor the growth of the nitrifying bacteria.

At the end of the week (yesterday) I tested the KH. It had dropped almost to 0. pH was also very low (test goes down to 6.2) I have seen this before with Soil Master Select. I added 2 tablespoons of baking soda. (Per math in post above, that should raise the KH by 4 German degrees of hardness). It was late last night when I added it, so did not wait for it to circulate to re-test. I also tested the NO2. It was off the chart. This has been developing over time, suggesting to me the bacteria are getting going, rather than the sudden release from the fertilizer tablets. (The pond ferts don't have NO2, anyway)

Today:

Tested tank
KH test was the API test, but I used 10 ml of water. At 7 drops (3.5 degrees) the water was no longer blue, but I would not call it yellow. At 8 drops (4 degrees) the water really was yellow.
pH was 6.6 according to 2 different tests.
TDS 538 (I have been dosing EI macros and micros, the baking soda last night, and ammonia, and remember those tablets!)

Tap water:
KH was tested using the 10 ml method. At 5 drops it was that 'not really blue, not yet yellow' and another drop made it really yellow. So 3 degrees (Side note: this is lower than average for my tap water).
pH over 8 by all the tests I have, probably 8.4 (Side note: this is higher than usual, but I have seen it this high before. Water company adds sodium hydroxide to the water)
TDS 221 (About average)
Chlorine and ammonia in the tap water show just about 1 ppm, exactly what it almost always shows. Chloramine in the water.

So...
Drained the tank down until the water was lower than the top of the substrate, but perhaps still an inch or so in there.
Re-arranged the rocks. Added some more rocks (so I really will pretend the rocks and substrate take up 8 gallons of volume.) This caused a very small amount of clouding that settled very quickly.
Cleaned the filters. They had some silty stuff, from the substrate. I have sponges over the intake and they had some plant roots and dead Duckweed on them. I was not too aggressive cleaning them, more sloshing the media in the used tank water, not really squeezing them much at all.
Refilled. Hose was aimed over the rocks so it did not stir the substrate much at all, and the fill was almost perfectly clear. Not quite, but an hour of running the filters and it was clear.
The plants did not like the ammonia. Anubias was in very bad shape, but new growth showing. The Vals were soft at the last few inches of the leaves, but the crown, root and several inches of the leaves were fine. I am sure these will recover. Water Lettuce not affected. Duckweed and Azolla are reduced, but what is still there is either dead (a lot of duckweed) or thriving (both Duckweed and Azolla have green healthy leaves, but not many of them.). I have lost a lot of the Azolla, and I do not know where it is. Gone.
Hornwort probably won't come back.
Added dechlor (Sodium thiosulfate- does not lock up ammonia)
Added 2 tablespoons baking soda directly into the flow from the filters. Slowly. I think it dissolved almost instantly.
Trace minerals. I used Seachem Cichlid trace, intended for Rift Lake fish. I have used it before and seen almost no response from the tests. It does have a very low level of Ca and Mg, and has many of the trace minerals plants need.
Ammonia.

Tests done within a few minutes of filling:
KH 5 German degrees of hardness. Tap water about 3, added enough baking soda to make it closer to 7, but tested so soon it was probably not well distributed. Will test again tomorrow.
pH 7.8, tested with 2 different tests. Note that this is lower than the tap water that I just added. The test (API high range) was really different, and so obvious that it is not 'user error'. I read the results right. The other test (a lab quality pH strip) agreed.
TDS 270 (Higher than the tap water, but seeing all the stuff I added, I am not surprised.)
Ammonia 4 ppm.
Chlorine was neutralized right away, per 3 different tests done a few minutes apart.

Tests done about an hour after tank had been refilled, water circulating:
Nitrite: 5 ppm. Hm. Hm. mmmmmmmm. Maybe the last test where it was WAY off the chart was really WAY off the chart? Then even though I got rid of almost all, there was some clinging to the substrate, and is now in the water. Darn, I hoped it would be lower.
NO3: under 20 ppm.
pH 8.4 per 2 tests (Gosh, back up again- glad there are no fish in there!)
KH: This was tested with the strips, and showed higher than I would have thought, between 200-300 ppm (= 11-16 degrees) Hm. I wonder if the pond 'tablets' have dumped another dose into the water. They sure got stirred around when I put the rocks in.
GH = 100 ppm = 5.5 degrees. (All my other GH tests are old, no longer work, so this strip is the only way I have to test it)
 
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