Dosing with Grubs - My DIY Fert Regime

This post started as an email to another forum member after our recent discussions on how our fert regimes were so different.

I figured I'd post this info for all to see as it may prove useful or interesting for others.

My particular approach is just the end result of starting with some known methods, comparing them and tweaking them over time...until I fell into what I do currently. I mix my own "brew" from dry chemicals because I like to tweak the mix to suit my plants and my mood.

Essentially I started on PMDD, then added a little Phosphorus...which brought me closer to PPS (Classic or Pro take your pick) and I do water changes to reset the tank as with EI. What I do now is close to a 1/2 strength PPS-Pro with EI style water changes (no test kits required!). I keep my water column dosing lean in order to grow some tricky Australian native Rotalas (R. mexicana, R. occultiflora)...but it seems to work for most other things. Tonina still rots for me though!

I'm using Eastern Suburbs Melbourne Water...which comes from heavily forested catchments that are closed to human landuse.

Very clean. Very Soft. Ph ~ 7, KH 0-1 dKH, GH = 0-1 dGH.

I dont bother boosting KH any more I used to add Sodium Bicarb to bring KH up to ~4 dKH but some posts on other forums dispelled the "PH swing" myth for me and I decided there was no need. My fish and plants have been very happy at KH 0-1. My CO2 is on a timer. pH in the tank is 6.6-6.0 most of the time.

I buy my dry chemicals from Duralite as they are local, they had CaSO4, and are cheap (most dry chemicals are only $3-4 per kg) Dave @ Aquagreen has most of these cheaply too.

The point of this post is just to put the info "out there" for reference as what works for me in my high-tech 6ft "Dream" tank (600l) predominantly but I do this for all my CO2 tanks. Growth over the last few months has been explosive. My Madagascan lace is sending up its 4th flower spike, Pogo has stems as thick as my finger, Blyxa japonica reaches 30cm high and I'm pruning constantly (too often!).

For my small tanks I just use the proportionate amount (e.g. in my 70l I dose 0.7ml of Macros/day.)

I aim for 50% waterchanges each week "EI-Style" - the water goes into the rainwater tank and is used to flush the loo! I break out the test kits once every couple of months to check the tank is still on track... which it normally is.


Note: 1 ppm = 1 mg/l

DIY GH Booster at Weekly Water Change
174g K2SO4
108g CaSO4
121g MgSO4

Mix powders together in a jar - makes around 400g (I make this amount because my digital scales only weigh to 500g)

I dose approx 4 teaspoons in 200l at each weekly waterchange (i.e. enough raise Melbourne tap water to ~ 4 dGH). I just spoon the powder into the tank as the water is refilling. The CaSO4 can cloud the water a little for 6-12 hours as it is slow to dissolve.

Analysis:
K 19.5%
Ca 7.5%
Mg 3%

Ca:Mg = 2.5:1

My "old" recipe was similar to Seachem Equilibrium with a Ca:Mg = 4:1 but with very soft water additional Mg gives various Rotala sp a real bost. I got this gem of information regarding Ca:Mg from kekon's thread on APC.


Daily Ferts - Trace Nutrients

I use REXOLIN APN MICRO MIX, a chelated trace mix for hydroponics from http://www.duralite.com.au Cost was $13 for 1kg. I believe it is similar to the Simplegrow mix Aquagreen now sells and isn't all that different to the Plantex CSM-B the Americans are fond of.

Elemental Makeup:
Iron DTPA 6%
Manganese EDTA 2.4%
Boron 1.1%
Zinc EDTA 1.3%
Copper EDTA 0.25
Molybdenum 0.25%
Cobalt EDTA 0.03%

Stock Solution = 125ml (yes only a small bottle)
20g Rexolin APN trace Powder.
fill to 125ml with Water.

Dose 3ml into 600l every day.
Equivalent Daily Dose of Iron: 0.05 ppm/day Fe


Daily Ferts - Macro Nutrients

My Stock Solution = 125ml (yes only a small bottle)
10g KNO3
1.5g KH2PO4
7g MgSO4.7H20
10g K2SO4

fill to 125ml with Water.

Dose 6ml into 600l every day.
Equivalent daily dose:
NO3 = 0.5ppm/day
PO4 = 0.08ppm/day
K = 0.6ppm/day
Mg = 0.06ppm/day


I use small stock solutions - only 125 ml because I dont use a lot (lasts about 2 weeks) and I like to tweak the recipe each time the bottle runs out - perhaps a little more P and a little less NO3 one time, a little more Mg the next.

I bought a little 500g digitial scale on ebay and it only takes me a few minutes to whip up a fresh batch.

DIY Substrate fertiliser balls
I mix a little Australian native Osmocote (it has low P) and a pinch of blood and bone into some laterite clay and roll them into marble sized balls. I'm guessing there are 6-10 little osmocote balls in each marble sized clay ball. Every couple of months I stick a couple in the tank under the heavy root feeders (Madagascan lace, Lotus, Crypts....and I believe they have been the saviour of my Rotala mexicana). Its been noted on this forum several times before (e.g. here) that substrate fertilising with low watercolumn levels seems to benefit some Australian native plants. Dave's Dino-Dung would do the same job here.


Comparison to.....

EI dosing

I'm comparing to this post of Tom Barr on his site where rather than just talk about spooning in dry chemicals he gives a more "analytical" EI method.

Stock Solution = 1000ml
60g KNO3
10g KH2PO4
25g Booster (12g K2SO4, 2.5g MgSO4)
in 1000ml water

Dose 5ml per 20 gal (75litres) daily
Equivalent daily dose:
NO3 = 2.5ppm/day
PO4 = 0.5ppm/day
K = = 2.1ppm/day
Mg = 0.02ppm/day

Trace - 2.5ml Tropica master Grow/Day = ?? ppm Fe

PPS-Pro
PPS-Pro reference

Stock Solution
59g K2SO4
65g KNO3
6g KH2PO4
41g MgSO4
in 1000ml water

Dose 1ml /10Gal (38litres)
Equivalent daily dose:
NO3 = 1ppm/day
PO4 = 0.1ppm/day
K = = 1.4ppm/day
Mg = 0.1ppm/day

Trace (80g in 1l dosed 1ml/10gal) = 0.13ppm/day Fe


So there you have it. My dosing is a little leaner than PPS-Pro (but I dose clay-balls into the substrate as well) and a lot leaner than EI. I do like the waterchange regime of EI and the fish seem to also. As we re-use the water for the loo I dont mind the water use - my water changes dont keep up with the "demand" anyhow.

With low dose levels its important to keep up the dosing daily or every other day. If I skip a couple of days in a row Nitrate can bottom out to zero and I find Ludwigia's and Pogo start growing a lot of unsightly roots into the watercolumn. Consistent, but low concentrations is my goal.

When we went away for a couple of weeks I just dropped in a double dose for the couple of days before we left and came back to a jungle.

Hope this post is useful to someone.

*looks at time* /slap!

Edit: - I left out three pieces of critical info.

1) When I measure them with test kits I'm getting NO3 = 1-5 mg/l and PO4 = 1.0mg/l.

2) I have 80 threadfins, 40 spotted blue-eyes, and 15 Corydoras sterbai in this tank - presumably they add some nitrogenous waste.

3) Credit where credit is due. I developed my confidence in calculating dose rates etc from this page and compared the numbers to what Dave posted for PMDD and Gilberts Brew. From here I just selected the range of values that seemed like a good starting point. Later I discovered I had essentially reinvented PPS-pro for myself. After reading a couple of posts by kekon on APC (one and two) I was convinced that low NO3 in particular was better in soft water and that a little extra Mg made all the difference in soft water.