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Discussion Starter · #1 · (Edited)
I started this hobby on an impulse and have been buying a little and a little. For trying to do a low light tank using as little plant food as needed. The problem is my water is stripped of nutrients thus have to dose even if I mineralize the substrate. After finding that the end result of diy light fixture cost more than a new 1 I started calculating cost of ferts. I compared dry and liquid. I like using Seachem for buying individual bottles I get more nitrogen. Nitrogen is a must for my plants. It is like buying vit. C vs buying a multi wth some Vit C.
My plants and tank here last post. This is comparison is for a NPT

Liquid ferts from Dr Foster's purchase - Nitrogen, Iron, Potassium, and Excel.
The cost with shipping $32.

Dry ferts from greenleafaquariums.com purchase Iron,Magnesium sulfate, CSM + B. and Excel(500ml).
With shipping cost $44.6

For me the dry ferts last 2x longer than the liquid.
 

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Dry ferts are just fertilizer concentrate. You're paying for the fertilizer instead of paying for water with some fertilizers in it.
 

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Discussion Starter · #3 · (Edited)
Dry ferts are just fertilizer concentrate. You're paying for the fertilizer instead of paying for water with some fertilizers in it.
True but when you are not calculating the cost at the end it seams cheaper to pick up a bottle of plant food a local pet store for $9. Then when you have to get another type of liquid and another you start wondering which way is cheaper. Tis the reason for this tread.
 

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Dry ferts are WAY cheaper. I spent about $40 almost a year ago and am still in good shape, dosing EI on a 92G tank. Mix a stock solution and you have the equivalent of liquid ferts, plus you make concentrations that you want to make dosing even less complicated. Only way to fly if you ask me.
 

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Commercial liquid fertilizers are bottled water, with minute quantities of chemicals in them. They are many times more expensive than the dry chemicals. If your calculation shows the end cost isn't much different you have made some big errors in in your calculations. http://www.aquariumfertilizer.com/index.asp?Option1=cats&Edit=2&EditU=1&Regit=2 has KNO3 at $3 per pound, KH2PO4 at $5 per pound, and CSM+B at $12 per pound. We dose these in a ratio of about 4 parts KNO3, 1 part KH2PO4, 1 part CSM+B, so we would pay 4 x $3 + $5 + $12 for enough ferts to last at least 3 years for almost any home aquarium. That is less than $10 per year. Using the Seachem line of fertilizers, dosed at the same rate would cost at least 4 times that much, probably even more. And, this is a conservative estimate. There isn't the slightest chance that any commercial liquid fertilizer line can cost less than twice what the dry chemicals cost.
 

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I use dry ferts and I can say its much cheaper. Dry ferts should last you a lot longer than just 2x. I used an entire bottle of nitrogen supplement just to keep my two tanks at barely 5ppm for a month, I have since been using a bag of dry KNO3 for two months and you cant even tell that I've used any.
 

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This is copied from Griggs' site, pretty much answers the cost question:


"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.
  • Total cost for one dose a week with dry nutrients 6.2¢
Seachem products cost 44X as much per week. Note these prices do not include shipping charges and there are some rounding errors. So that pretty much settles that one."
 

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I used liquid in the begining and found them to be way too expensive. I would run through a bottle in no time. Once you have your mixtures calculated you are good with dry at very little cost.
 

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I'm just like you Hilde, I bought some flourish fertilizers because it was all my LFS had in stock. It's easy to use them if you have a small tank, but even then you end up paying a lot in the long run. I would say I'm glade I started with liquid ferts only because its been easy for me to start without overdosing very easily, but the minute I use up these liquid ferts I plan to switch to dry because, like most others say, you get so much more for what you pay. The bottle you buy of dry fert KN03 lasts you way longer than a bottle of flourish. I honestly think If I stick with my liquid ferts, Ill end up having to buy 2 or 3 bottles of liquid ferts (if not more) for just 1 bottle of dry ferts.
 

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Discussion Starter · #10 ·
I can't decide whether to stick with wet or go with dry, for I will always need Excell. Also when I move to Florida I will need Eco Complete. Dr Foster has a good sell on a combo, Flourish, Excel, and iron for $11. Shipping cost is reasonable too. At Greenleaf dry ferts Excel and Eco complete the shipping cost was $14. I am going to wait until I am down in Florida and see if someone locally sells Eco complete.

For my 29 gallon tank I have substrate mineralised my version thus only dose 1ml of liquid ferts. Most don't dose when they have mineralized substrate but have to here for the water is very very soft. Perhaps in Florida won't have to dose the water.
 

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Whatever you choose to go with is up to you; other users have already stated that dry fertilizers are much cheaper.

Excel is not always required; you could just get a pressurized CO2 setup. Again, like dry fertilizers, pressurized CO2 will be cheaper than Excel (in the long run).

Flourish Excel and Iron for $11 is quite expensive. As already mentioned, with bulk fertilizers, you are costing you less than 10 cents a week to dose a 60g tank. This includes all the macronutrients (Flourish Excel and Iron are good as an alternative carbon source and micronutrients, respectively, but do not provide any macronutrients). If you buy the Seachem macronutrients, it costs even more...

Mineralized substrate is nice, but if you have a high light tank, there is no avoiding dosing fertilizers into the water column.
 

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Discussion Starter · #12 ·
My goal is to keep my 29 gallon tank low tech.
I did some more research and found that the dry ferts would probably last 7xs longer than the liquid ferts. The dry ferts would cost $20 more. Probably going to stick with liquid ferts until have used up what I have.
 
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