mkendle87

I really like the look of natural or play sand as a substrate in a planted tank but I have heard that it is not a very good cap for dirt. Im getting ready to set up a new 29 gallon tank and would like to use the sand as a substrate. I wasent sure if it was possible to cap other substrates such as eco complete or fluorite with sand or if there was any way to grow good plants in straight sand. I am also still considering dirt. Any advice would be greatly appreciated.

BruceF

I’ve always used play sand. You can use it to cap anything you want. If the bottom layer has too many spaces the sand will slowly fill them so it is best in that case to just mix the sand with them to start. Unless you need to remove a large rooted plant I don’t find planting or un-planting to be all that much trouble. The longer it is in the tank the easier it is to deal with.
These days I use dirt with about an inch of sand to plant as a cap. I usually plant the whole tank all at once into the dirt capped with about half the sand. When I am finished planting I add about another half inch of sand to clean up and straighten out the surface. I use a spray bottle to keep it all wet as I plant. The spray also helps keep the glass clean. When it is all planted I slowly trickle water into a dish or onto some saran wrap until the tank is filled. I don’t wash the sand anymore I just plant in this way to begin with.
Diatoms are almost always a problem in a newly planted play sand tank but I just keep after cleaning them off the glass and such. They will subside in time so I really don’t worry about them much. I can’t really compare the problems with anything else because I rarely use anything else.

asukawashere

It depends on what kind of plants you want to grow. I wouldn't try to use sand as a cap for a large-grain substrate (as BruceF said, the sand falls through the cracks), but it is a viable cap for dirt. I prefer pool filter sand to play sand, but that's a personal preference rather than a rule.

As for plant selection, anything that doesn't feed heavily from the roots is fair game (and anything that needs more root feeding can be potentially supplemented with root tabs). I've had great luck with Vallisneria and Sagittaria subulata in sand, and of course any rhizome plants (Anubias, Java ferns, Bolbitis) don't care what the substrate is.

Emily6

So I'm looking re-scape my current high-tech tank and am also considering pool filter sand (the grains tend to be a little bigger than play sand, right?). I currently have flourite black sand mixed with flourite black gravel. Would it be a good idea to just cap what I'm using with the pool filter sand? Supposedly flourite substrate never expires.

My other big issue is super soft water- so something that added minerals would be a bonus over something like turface or the like that will draw minerals out of the water column.

Basically, I've never used pool filter sand before.

Diana K

PFS has more consistent particle size, so it does not pack together like most play sand.

I have used Turface and related products. They remove carbonates, but not calcium or magnesium. The KH drops, allowing the pH to fall. The GH remains stable.
I have addressed the KH problem in 3 different ways.

Lake Tanganyikan tank: Mix coral sand with Turface.
Looked horrid. (I like a dark substrate).
The Turface no longer removed the KH from the substrate. I still needed to alter my tap water, adding minerals, for a water change, but the tank was stable though the week.

Hard water tanks: Add coral sand, oyster shell grit or limestone sand to the filter. I use nylon stockings as media bags.
Like the Lake Tang tank, I would alter the tap water to make it right for a water change. Then I would monitor the tank through the week, and sometimes had to add baking soda to keep the KH up.

Soft water tanks: Let it drop! Except when I was doing a fishless cycle. The bacteria need the carbon from the carbonates, so I kept the KH at least 3 German degrees of hardness with baking soda. It took dosing every other day to keep it above zero.

Emily6

Thanks for the descriptions of your solutions at home.

So I bought some Seachem Meridian- it's meant for salt water tanks and will buffer the pH. I'm a little nervous about it so I think I'll test a sample in a nano first. If it's ok, my plan is to re-use my flourite sand in the areas I plant (put in fresh root tabs and divders of some sort) and then create open spaces with this new sand- basically a 50-50 space division.

I wanted to try the sachel in the filter idea except I don't have an extra comparment for that- just 3 and I don't want to bump the ceramic beads, the filter fiber or the sponge.

Since I live in a small apartment, I can't really pre-treat my water before a water change (no garbage bins or anything large to hold 20+ gallons in). I'm also not around during the week so I can't really monitor the parameters throughout- I have to make small changes every weekend. Again, makes me nervous with this new substrate but I'm trying to subscribe to the "nothing ventured, nothing gained" theory.

I'll post my results after the test tank.

tat

Sorry to ask, but what are your PH/KH/GH today? Do you really need to buffer the PH?

Emily6

my GH is 0, my KH is 2-3. The pH starts at 8 but with the COs hits 6 really fast- within hours. WHich is the real problem I'm trying to address without having to constantly be adding baking soda or Equilibrium.

tat

In my opinion there isn't any problem on the PH swings due to CO2 injection.

Diana K

Good idea to use a substrate like that when the GH is so low. Monitor it, and make sure the GH, KH and pH are staying where you want them.

No need to get RO water for top off: Your tap water is near enough to nothing!