Support for exhausted substrate

[Peter]

Dear Tech Support,

My current fish tank (50x22x22in - approx 320l/84gal) has been set up for 5 year. I believe the minerals/fertilizer that was originally in the substrate should have been exhausted by tge end of the 2nd year. Since then I had been inserting Flourish tabs into the gravel at the rate of 10 tabs every 3 months. Besides this, I dose with Flourish at the rate of 1.5ml at each weekly 25% water change and 1ml every alternate day thereafter. Flourish Excel is dosed at 8ml daily and Flourish Iron is dosed 1ml twice a week. I have CO2 dosing at 1 bubble every 2 seconds and my lighting is 2x36W with full reflector for 11 hours. My water parameters are:

ph 6.7 - 7.1
KH 2 - 3 dH
GH 2 - 3 dH
Nitrate 5 - 10 mg/l
Phosphate <5 mg/l or not detectable.

The tank is filled a 10 octos, 15 shrimps, 5 corys, 2 SAE and about 30 to 50 varying size of guppys at any time. The fishes are feed 3 times per day with most food consumed within 2 to 3 minutes.

My plants consist of Crypts, Hydrophila difformis, Ceratopteris thalictroides and Anubias barteri var. nana. The plants are flourishing with minimal algae. Do you think the current fertilization of the substrate with Flourish tabs is adequate.

Peter

[Tech Support CH]

Depending on the type of substrate used, the substrate may still be viable. Our Flourite is a mined product that will retain its benefits for as long as the material is visible. Extra supplementation is beneficial and will not harm the plants.

"The plants are flourishing with minimal algae"

This tells me that what you are doing is right. If I where to change any of your levels it would be your GH. Many of your plants and fish will benefit from higher calcium and magnesium levels. For most planted aquariums I recommend a minimal GH of 6 dGH. This will provide enough calcium and magnesium for the hard water plants and fish.

To raise your GH I recommend the use of Equilibrium.

[Peter]

Dear Tech Support,

Thank you for the response. My substrate base is a laterite mix from dennerle. Based upon your reply I will thus not touch the substrate.

With regards to the GH, I will try to raise it. The difficulty here is my local water typical has a GH of less than 2 and to raise to 6 will require a fair amount of Equilibrium.

Thank you for your assistance.

Regards
Peter

[Tech Support CH]

You are welcome.

Each 1 tablespoon per 20 gallons dose of Equilibrium will raise the GH by 3 dGH. So it will not take that much Equilibrium. You could try just one dose and that should raise it to 5 dKH.

[Peter]

Thank you.

I will raise the GH but would spread this over a 2 to 3 weeks as I am worried of shocking the Crypts and causing them to melt.

Regards
Peter

[Tech Support CH]

Good idea! Your Crypts will love the higher GH but you don't want to shock them.

[v.bow]

quick question about the flourite. so as long as i can see the subtrate , it is not exausted?

[Tech Support BB]

That is correct. To be realistic about it, you will never exhaust Flourite. So much of its makeup is iron that it would be generations before it is "exhausted." To get an idea of what we are talking about, imagine dissolving a large piece of limestone in strong acid. If you have ever played around with that type of situation, you know that even a small piece of limestone can completely exhaust a large amount of liquid acid. Now understand that Flourite is basically insoluble, even in acid digestion tests. The ONLY WAY for Flourite to lose iron is for the plants to absorb it. Do you worry about replacing the ground underneath your lawn every few years? Neither should you worry about Flourite. Once it's there, it's there.

[v.bow]

ok so then since its iron, does it act as a carbon source? not enough but it still does correct?


will i need to dose with flourish fert?

[Tech Support BB]

Flourite is not a carbonaceous substrate. It is rich in iron, not carbon.

You may need to dose with Flourish, most people do. It depends primarily on the type and quantity of plants in the tank.