PMDD Pre-mix questions

[Urglytank]

Hi everyone, I am new to this forum.

I have just received my PMDD premix from Aquariumfertilizer.com. I understand that buying premix one is not a better choice than buying separated chemical compounds however that 5lb PMDD premix is now sitting in front of me.

I am trying to make the first mix but I am hesitating to do so as I am not really sure of the amount to mix.

My questions are:

1- Is 1/4 cup exactly 4 international teaspoons to add to 500ml H2O?
2- Do I have to keep the solution in the fridge as per Plantex CSM+B?
3- Does the current PMDD pre-mix contains any phosphate?

Kindly help

 

[Tom Barr]

I do not know what precisely pre mix is, however, old school PMDD has no PO4 added.

You may use Fleet enemas available from local drug stores and pharmacies, these are solutions of sodium phosphate(It will say this on the label), and you might search around on the web to get something with just water, no scent etc.

1 tablespoon is 15mls in volume.
You can add 1 ml of 9M HCL or equivalent and not need any refrigerator.
Do not mix the enema with the solution.

See the Estimative Index "daily PMDD + PO4" routine for a better run down. You do not want to mix a trace mix with PO4 based things. Fine for the tank, but not at high concentrations.

Regards,
Tom Barr

 

[Urglytank]

Many thanks for your advice Tom. I am challenging this PMDD pre-mix for a while until I can find a better result on my part.

Since I start dosing this a few days ago, I can see some good result as my plants start pearling however I got BBA coming along. I am having inconsistent DIY CO2 in my 40G tank. I am not sure whether PMDD also contributed to the cause.

 

[Tom Barr]

Well, if you strongly limit say PO4/NO3, the plants will not use much CO2.
Adding nutrients rules out those as limiting, now you have a CO2 issue

Doh!

This is the root problem, you need to adjust that and add some Excel till the BBA goes away. Since CO2 was non limiting at first, now it's limiting, but the nutrients are not, you need to add more.

Otherwise, folks end thinking that nutrients, not CO2, was the issues and why they got algae(very common). But this is wrong, the CO2 was not non limiting in both cases, the nutrients caused a secondary confounding effect not present in the first example.

You need to have non limiting nutrients and CO2, and if you want to modify growth rates, speed them up or slow them down, use light to do that.
since that is where all plant growth starts....................

Regards,
Tom Barr

 

[Urglytank]

Appreciate your kind help Tom. Now I see your points. The only issue for me is the availability of certain stuffs in my location i.e. Flourish Excel, test kit..

Everything so far has been done trial and error base - I even don't know my water parameters.

 

[Dmaaaaax]

When making my Plantex CSM+B, I made a rookie mistake by making it up with my tap water. I got sediments the next day that I thought was just undissolved minerals. It turns out my tap has a decent amount of phosphate in it and I was getting the Iron phosphate byproduct. I was not sure how much iron I lost so I had to make a new batch in distilled/DI water this time....no sediments.

 

[Urglytank]

I did my first PMDD Pre-mix (4 tablespoons to 500 ml distilled H2O). If I am not mistaken, 1/4 US cup is approx. 4 tablespoons. The ratio is based on the instructions from Aquariumfertilizer.com.


Previously I used a liquid fert called White Crane Plant Plus from Aquatech. The fert is packed in a small bottle - actually it worked well for my plants however I suspect the fert is bottled from PMDD and commercially branded.


I am battling two types of algae now - BBA and the green spot on both of my tank. People recommended me to increase PO4 to eliminate green spot and increase water circulation to stop BBA and for both cases I have to add more CO2.

As per Tom's advice - My main issue is with CO2.