Why would you want to use bulk nutrients. Well here are some numbers.
If you are dosing 60gallons of water with Flourish Potassium you would need 100 ml to get to 20 ppm.
If you are dosing 60 gallons of water with Flourish Phosphorus you would need to dose 48 ml to get to 1 ppm.
If you are dosing 60 gallons of water with Flourish Nitrogen you would need to dose 30 ml to get to 10 ppm.
Flourish Potassium is $6 mail order for 500 ml. So if you dose once a week that bottle will last you 5 weeks. Cost would $1.25 a week to dose potassium.
Flourish Phosphorus is $7.50 mail order for 500 ml. So if you dose once a week that bottle would last you 10 weeks. Cost would be 75¢ a week to dose Phosphorus.
Seachem Nitrogen is $7.50 mail order for 500 ml. So if you dose once a week that bottle will last you 16 weeks. Cost would be 47¢ a week to dose nitrates.
Total cost for one dose a week with Seachem $~2.75. Note there is no shipping factored in here and there are some rounding errors.
To dose the same tank with bulk nutrients.
Nitrates 2¢ a dose.
Phosphates .2¢ a dose. Note that is 5 doses for a penny.
Potassium 4¢ a dose.
Total cost for one dose a week with dry nutrients 6.2¢
Seachem products cost 44X as much per week.
