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Mid-tech tank, dosing necessary?

2013 Views 8 Replies 4 Participants Last post by  LetDiceFly
I'm new to this and I'm trying a middle road approach to this, and I'm not sure which way to go as far as fertilizer goes. The only thing that I have been using so far is Flourish Comprehensive and what is in my substrate. The tank is pretty new and I have been having considerable growth as it is, without algae. It is 2.1 watts/gallon with CO2. The plants have been growing well except one that totally melted and is now regrowing and some blackening on the tips of the leaves on a lace java fern. The leaves on some of the plants may be paler than they were when I got them (particularly an anubias). I don't really have a frame of reference to know what the plants should look like healthy. I have some swords, hygro, and water sprite that are growing at a phenomenal rate. I'm new to this and I'm trying a middle road approach to this, and I'm not sure which way to go as far as fertilizer goes.


Tank has been set-up for about a month, but started with cycled media, substrate, etc), but then 2 weeks ago I added some Aquasoil Amazonia and the cycle was broken and the pH dropped to insanely low values < 6.0 (below the bottom of the range measured by API kit). I have been doing a lot of water changes to save my fish, although I lost a few catfish) but I am nearly cycled. I still have some ammonia but I also have NO2 & NO3. I am upset that there was no warning on the aquasoil that this would happen, I would not have put it in my tank.

Using and Flourish Comprehensive

15g tall (20x10x20in) tank
Eclipse 1 Hood
Replaced carbon filter cartridge with filter pad and Purigen
32w CF lighting (retrofit from the stock 15w) on 12hr/day
Redsea Turbo CO2 Bio-System (just installed)
Substrate (50% Flourite, 35% Amazonia, 15% large black gravel)

Fish: 6 female betta, 5 pygmy cories, 2 otos, and a juvenile BN Pleco.

Tap GH=10, KH=8, pH=8.0, no N compounds
Tank GH=11, KH<1, pH<6.0 (until I used baking soda to raise KH)
last test before WC Ammonia=0, NO2=0, NO3=10
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If the light is from screw-in CFL "power saver" bulbs, you don't have as much light as the "watts per gallon" would make you think you have. Those bulbs are very inefficient at getting light down into the water. If you are using them, you probably still have a low light tank, and little fertilizer dosing is needed.

But, if you retrofitted a PC light, the 4 pin type, with two parallel tubes, and are using a good reflector, you may have moderate light intensity. The tank depth tends to reduce the effective intensity. For this type of lighting, some dosing of NPK and trace elements would be desirable.
Thank you for your reply,

I do have the 4pin type bulbs using a retrofit with a good reflector.

I also have a high fish load, and I have nitrates in the tank, so I should skip the N, right?

I have also seen in posts that phosphate comes from fish food, and I see 1.2% phosphate in my betta pellets. About 12 betta pellets get processed through the fish in a day (zero waste, bettas are efficient eaters). Does this influence my dosing any? The other food is all frozen hakari bloodworms and daphnia and doesn't appear to have phosphate in it.

Right now I am thinking of using the dosing from the seachem chart leaving out the nitrogen and iron (I figure the fish are producing the N, and the Fe is in my Flourite/Amazonia mixed substrate). Does this seem to be a good place to start?
You do have a decent amount of light over the tank and Water Sprite and Hygro (what type do you have?) are fast growers and therefore big consumers of nutrients. If you want to keep things simple, you may be able to get by simply by increasing your Flourish dosing. I assume you are using Flourish Comprehensive? Contrary to the directions in the flourish link above, I add about a capful to my 10g low tech tank each week to every other week when I remember ;)

As far as knowing what "healthy" plants should look like, you can see pics of healthy plants in the PlantFinder
Yes, I'm using Flourish Comprehensive. The hygro is corymbosa 'augustfolia'.
Oh man, I totally missed the part in your post that you are using CO2 :oops:. In my opinion you definitely need to add more in the way of fertilizers...the CO2 will increase plant growth quite a bit even with 2wpg.

You can go the Seachem route for fertilizers but you will need to add more than they suggest. I can't be of much help with quantities since I've never used Seachem's line of fertilizers. However, you can read this thread for more info and a handy spreadsheet for using Seachem's ferts.

Should you decide to go the dry fert routine, EI is the easiest method to learn when you are first starting out with fertilizing. You should go with the amounts listed for a 10-20g tank. You can purchase a year's supply of dry stuff for about the same cost as a month's worth of Seachem's products.
Thanks for the info, I guess I'll look into the EI.
By the way, are you using the stock 32w bulb that came with your kit?

Those retorfit kits come with a saltwater 50/50 actinic/white bulb.
No, I'm using a SunPaq Dual Daylight 6700K/10000K. In fact I ended up with 2 new bulbs I have no use for, the bulb that came with the hood and the bulb that came with the retrofit.

I ordered some KHPO3 and KNO3, pretty remarkable how cheap it is.
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