confused about fert dosing

[illumnae]

I've been reading up past posts on fert dosing and i've turned my mind into mush i think...don't know what i'm doing right or wrong anymore I was trying out EI dosing because of the supposed ease at which fertilizing can be done (no test kits!), but it seems that complex mathematics is needed instead and i'm on the verge of ripping my hair out.

Listed below are my tank and fert specs...i'll be very thankful if someone can advise me on what i'm doing right/wrong if i'm intending to go the EI route:

Tank

• 4x2x2 feet
  • ~420 liters or ~110 US gallons
• Medium-Low plant density
• High bioload

Lighting

• ~3wpg using PL lights

CO2

• currently doing 4bps, may reduce to 3bps when fauna comes in

Fert regime (what EI recommends):

• 1.5 teaspoon KNO3 (3 times a week)
• 0.5 teaspoon KH2PO4 (3 times a week)
• 25ml Seachem Flourish Trace (3 times a week) - recommended dosage on bottle
• 15ml Leaf Zone - Gives Fe and K+ (3 times a week) - ~recommended dosage on bottle

It seems that i'm lacking Calcium and Magnesium and I was recommended to use Seachem Equilibrium once a week after my water change at about 1/3 to 1/2 the recommended dosage. Would this put too much K into my water? or is there already enough Calcium in the water like i've read in some posts such that i don't need equilibrium? Should i dose less KNO3 as the high bioload would give more NO3? Would i lack K if i cut down on KNO3?

All the above questions are plagueing me now, and i have no idea how to resolve all the mathematical ppm formula and what the plants need. At the moment, with the abovementioned dosing regime and no fauna in yet, my plants start bubbling about 1 hour after lights and CO2 come on.

Once again, I'd greatly appreciate it if anyone could help me out here with constructive advice and not just ask me to go dig up old posts, as it's what i've already done and emerged even more clueless than before.

[Shadow]

This is something that I frequently confuse as well. The recomendation from various fert dosing calculator implies that K+ ppm requirement is higher than NO3. Thus to get the right range of K+, we need to increase KNO3 or add K2SO4. However, I was reading some of the thread and most people does not does K2SO4.

Curently what I did is adding K2S04, My target for both K+ and NO3 are equal to around 10~12ppm

Sorry if I make you even more confuse, I confuse a well

Chuck's calculator:
K = 20ppm
NO3 = 5ppm

APC fertilator:
K = 10-20ppm
NO3 = 10-20ppm

EI:
K = 10-30ppm
NO3 = 5-30ppm

[luenny]

Hi Yi Xiang,
Welcome to the wonderful world of planted aquarium. How're your apistos doing?

- Luenny

[illumnae]

hey luenny my apistos are doing good =) nothing different from the rio mamores and my bitaes are lousy parents, as i update (though noone ever reads/responds to my posts) on the cichlid subforum =)

how are your discus doing?

[stephen chung]

Yi Xiang,

Mine is still not spawning..

[Shadow]

mine still juvenile

[PeterGwee]

Guys, you are wondering off topic. You might consider PM instead.

illumnae, the dosing plan is fine except that you might want to change the Seachem Flourish Trace to the regular flourish. If you do that, you no longer need the leaf zone product. Seachem Equilibrium is fine at 1.5 teaspoon only after the weekly water change. You do not need to worry about the K+ as long as more than 50% of your NO3 comes from KNO3 dosing.

Regards,
Peter Gwee

[stephen chung]

Yi Xiang,

Since it is EI (Estimate Index) so I also agar agar...

[illumnae]

Guys, you are wondering off topic. You might consider PM instead.

illumnae, the dosing plan is fine except that you might want to change the Seachem Flourish Trace to the regular flourish. If you do that, you no longer need the leaf zone product. Seachem Equilibrium is fine at 1.5 teaspoon only after the weekly water change. You do not need to worry about the K+ as long as more than 50% of your NO3 comes from KNO3 dosing.

Regards,
Peter Gwee

Hi Peter,

Thank you for your reply =) I'm relieved to hear that my dosing regime is ok and won't cause me algae problems. an LFS guy just told me to expect algae in 2-3 weeks max with my regime as he thinks i'm overdoing the fertilization.

I intend to change the Seachem Flourish Trace and Leaf Zone product to regular Seachem Flourish, but I thought it would save some money to finish the 2 bottles concurrently first before switching over. Do you think that is ok, or would it create problems?

1.5 teaspoon of Seachem Equilibrium is for my entire tank (420 litres) or for 80 litres as half of the recommended dosage?

One last question. If 50% of my NO3 comes from KNO3 then I don't need to worry about K+, but both regular Seachem Flourish and Seachem Equilibrium add quite liberal amounts of K+ in right? So would that cause problems?

Thanks again for your reply and time taken to help me out. Greatly appreciate it!

[PeterGwee]

Seachem Equilibrium dosage is for the entire tank volume. Excess K+ is not an issue at all.

New tanks often get hit by algae due to low plant mass (more plants more uptake of NH3) and low bacteria count (unable to convert NH3 into NO3 fast enough). In order to overcome this issues, you can simply do more large water changes to remove the NH3 buildup, add "mulm" from established tanks to speed up bacteria culture and add loads of plants to remove the NH3. EI itself is great since it eliminates all possible risk of nutrient deficiencies by means of adding nutrients in slight excess so the only possible trigger to algae issues usually comes from lack of CO2 or NH3.

Regards,
Peter Gwee

[illumnae]

Thanks again for the speedy reply Peter

Wow 1.5 teaspoons of equilibrium for the entire tank seems so little as compared to the 7 tablespoons recommended on the bottle

I think I should be good on NH3 conversion to NO3 as my tank is a rescape and my filter media was left intact from the old tank, only washed in old tank water so my bacteria colony should have survived...i've also already left the tank fishless so far (2 weeks) with the filter running and will probably leave it fishless for another week or 2 to let the plants root well and the hairgrass to spread, so the bacteria has loads of time to multiply the only fish will be a baby puffer put in to eat the snails and worms that sneaked in on my plants.

CO2 wise, i'm not sure how to gauge it well as the methods to find CO2 ppm rely on PH, and i was told that my substrate affects PH levels...so all i'm able to do is to go by estimation. i do 4bps, and my plants start to bubble about an hour or less after lights and co2 come on (i don't need to put CO2 in while the lights are off right?).

thanks once again for your advice and it's good to know i'm doing things right spent alot of $$ and effort redoing this tank, am really hoping it'll turn out well

[PeterGwee]

Get yourself a CO2 dropchecker then to measure the CO2. You can get the 4dKH standard solution off the web from folks selling it or just make do with a less accurate version of one with DI/Distilled water + baking soda. Since the 4dKH + reagent solution doesn't mix with the tank water and only have contact with air+CO2, you can be sure it is only CO2 that depress the pH. Target a pH of 6.6 with a KH standard solution of 4. The only down side with this method is the response time of the drop checker...ADA journal states a rough response time of 6hrs. You need to note that mixing the CO2 in the tank as evenly as possible gets more important in larger tanks. The CO2 system needs to be responsive such that it will achieve the target CO2 level within an hour or less once it's turned on.

Regards,
Peter Gwee

[illumnae]

Get yourself a CO2 dropchecker then to measure the CO2. You can get the 4dKH standard solution off the web from folks selling it or just make do with a less accurate version of one with DI/Distilled water + baking soda. Since the 4dKH + reagent solution doesn't mix with the tank water and only have contact with air+CO2, you can be sure it is only CO2 that depress the pH. Target a pH of 6.6 with a KH standard solution of 4. The only down side with this method is the response time of the drop checker...ADA journal states a rough response time of 6hrs. You need to note that mixing the CO2 in the tank as evenly as possible gets more important in larger tanks. The CO2 system needs to be responsive such that it will achieve the target CO2 level within an hour or less once it's turned on.

Regards,
Peter Gwee

If the response time of the drop checker is 6 hrs, i'll need to check the drop checker 7 hours after i turn on the lights/CO2 to obtain my result, and repeat the test with the drop checker in many different locations in my tank to ensure that the CO2 is evenly distributed?

Also, it's ok that my CO2 is only on when the lights are on right?

Thanks once again!