Well, if Ca(NO3)2 is all you have avail, then you can use about this same amount, but use about 60% of the suggested KNO3.

You only add some Ca(NO3)2, once a week.
I'd try and get CaCl2, or CaSO4 if you can, it'd be odd if all you can get is Ca(NO3)2.

You can use it, but I'd likely use /add K2SO4 if that's all I had available for Ca to add to the K+.

So on WC day, I'd add about 3/4" tsp Ca(NO3)2, and 1 teaspoon K2SO4.
No KNO3.
Add about 1/2 teaspoon epsom salt 2x a week.

But after, until the next water change, KNO3

Regards,
Tom Barr

Tom, what exactly do you mean by "But after, until the next water change, KNO3" ?

BTW, I don't see any reference to KH2PO4. Would this be okay ?

Sun: 50% WC, 3/4 tsp Ca(NO3)2, 1 tsp K2SO4
Mon: 1/2 tsp MgSO4, TE
Tue: 1 tsp KNO3
Wed: 1/2 tsp MgSO4, TE
Thu: 1 tsp KNO3
Fri: TE
Sat: rest day, enjoy watching the tank. Good time to look for any deficiency

Or should I cut the KNO3 on Tuesday and only dose it once on Thursday ?
If KH2PO4 is needed, 1/4 tsp 3 times a week ?

Please advice, TIA and warm regards.

You have a 160 Gal tank.

Add Ca(NO3)2 on the water change day, the rest of the week, add KNO3.

PO4, TE, Etc.......you do as you where doing.
All you are doing is adding more GH on the water change day is all.
Ca and Mg.

You get plenty of K+ from K2SO4.

This way you can add more Ca, without having to add Ca(NO3)2 all the time.
You can if you want to, and also add K2SO4 along with Ca(NO3)2 and not use KNO3 at all.

Up to you and how much Ca you want.
I use CaSO4 namely for additions of Ca.


Regards,
Tom Barr

Tom, you have been very helpful. BTW can I safely use this chemical called Plaster of Paris ? Someone told me it's Calcium Sulphate, CaSO4·0.5H2O , Plaster - Wikipedia, the free encyclopedia .

If your answer is yes, then I figure it will be 1/2 tsp of that CaSO4·0.5H2O and another 1/2 tsp of MgSO4 after a 50% water change?

I believe the pp is CaSO4.
I also know it as gypsum, I'm more inclined to get it via that way, but if it's 100% CaSO4, or close, then use it, especially if very fine ground.

It does dissolve but takes more time than say CaCl2, but it's a lot more soluble than CaCO3.

Yes, that amount should relieve most any issue you have with GH, dose that amount 2x a week.

Since this thread is about using the PMDD liquid dosing method, generally daily, add 2 teaspoons of CaSO4+ 1 tsp of MgSO4 per week's worth of dosing.

Note, since it's less soluble, as is K2SO4, plus you have a larger tank.......you may consider using a larger volume, say 2-5 liters at a time for a 2-4 week batch for the macro's, and 500mls for the traces.

The confusing thing and at the same time the flexibility here is that you can customize the solutions to meet any goal or demands you desire for the tank.

This is one reason I went to EI type of dosing suggestions for folks, simple made it easier for folks.

There are trade offs, but not that many relative to the usefulness.
Same with any approach.

Regards,
Tom Barr

For a 160g (600 Litre) of water, that will only give (with Fertilator) 2.83ppm Ca and 0.16ppm Mg. I have read many times that the target ppm for Ca and Mg are 10ppm and 2ppm respectively. Reason for this Tom?

Don't you have some in your GH?
Have you tested it for Ca and Mg specifically?

Mg can be added as needed, but you really do not need a lot, and adding that much per day is fine unless you have a lot of light/CO2. TMG also has some Mg as well.

If you know how to get the ppm's, why are you asking me?
It sounds like you have a certain notion of what the range should be as it is...........
so do that.

It's not going to hurt.

However, I've never suggested 10 ppm of Ca and 2 ppm Mg anywhere ever.
So as far as "optimal", that's rubbish.

I've done a rather exhaustive survey of Mg and Ca mineral content in aquatic plants, about 3-4: 1 ratio is what's found in them. They have the same levels whether or not that external Mg is 0.1 ppm or 2 ppm or even 52 ppm like our well water at the lab etc or in in natural systems, same for the most part with Ca. I wrote 15 pages about it on the Barr Report newsletter with supporting details and primary research references.

External concentrations can vary widely, and we see excellent growth with both high and low GH's in aquarium plants.

My reasoning for telling to add little is to see if it's limiting.
You should see a dramatic response if so.

If not, perhaps you have enough from the tap already...........
So it's one issue you may not even need to worry about, but if you feel 10ppm Ca and 2 ppm Mg is what you want, you seem to know what to do already.

Higher GH's will certainly not hurt.
I prefer them fairly high myself, about 5 or higher.

I use the GH scale and add extra mix of a known ratio of Mg/Ca together.
That's easier than messing with specific Ca and Mg ppm's and does not even matter what the individual Mg/Ca levels are since the added extra is at the right range.

Adding 5x more Ca and 10 x more Mg is fine and if that's your target, go for it.

Regards,
Tom Barr

Great stuff Tom and thanking you for all your patience and kind assistance.

Hey Tom,

After a horrible experience with PPS-Pro in my 20 gallon tank I have decided to try this method. I have a quick question for you. I wanted to make this solution but when mixing up the batch, i only ended up using 900ml. of water, instead of the full recommended 1 liter. how will this effect my concentrations in the tank at dosing time? and how should I adjust the mls. that i add to the tank??? thank you very much.

sean

Rather than having a horrible experience with this, or any methods, EI included, I generally suggest failure at a method something you might want to conquer.
PPS pro should work............
It might be a bit more work than some like, or more complicated.........however, the nutrients used are the same as EI..........the EI method just added more of them.

You can vary EI to leaner routines easily as well.
But adding excess, or providing non limiting ranges should pose no threat to any well run tank unless they are really high(much more than I typically hear about from folks that test to check.)

What I'm saying, do not blame the method, look at it as a learning experience and try to see why the failure occurred, do not blame the method.

It's our own fault when we fail, just try to change things, or see where you went wrong. Be honest about it and get back up and try it again till you succeed.

You learn a lot more this way and can use any method. And then you can tweak the method you chose as best suited for you, in a much better way.

We all have goals we want out of the system, and then there are the trade offs we are willing to do to have them.

PPS is not far removed from PMDD +PO4, nor EI using liquids.
Ratios are slightly to somewhat different, but the things are added are still the same.

What I'm saying now is that if you failed there, you will very likely fail here, but it may not having thing to do with the dosing method.

It generally is CO2 related.
Many folks using PPS had BBA and other issues with algae, of which they where CO2 related in the root cause.

Many found that algae went away when they dosed less.
This is secondary limitation -> the PO4 limitation reduces the plant's CO2 demand, so the intensity of the CO2 limitation(root cause), is greatly reduced, the road block is now low PO4, not CO2 as much.

Not taking into account CO2 carefully and critically often leads folks into blaming the wrong parameter for an algae issue.

I beat these folk's arguments up pretty good in most any debate, but it's because I know how to induce algae(few ever bothered to do this- it's a very powerful tool) and also can consistently produced non limiting CO2, light and nutrient levels for dense planted tanks(eg a control tank to base such comparisons against...........without which you cannot say a whole lot).

If all you did was mix up 900mls instead of 1000mls, simple multiply by 1000/900 for concentration or 1.111.

I'd really suggest focusing a lot of using less light, and really making sure the CO2 and current are good.

Search here about CO2, CO2 mist, CO2 and current etc.................this is 90% of growing plants with CO2 enriched methods, the nutrients should be otherwise easy if you keep up on the gardening and general maintenance.

Another thing about initial experiences without many methods, you learn more as you go and remember where you might have gone wrong later.......so after trying 2-3 dosing methods, you are much wiser than the first time(hopefully).
So do not believe everything you see or think.


Regards,
Tom Barr