I'm glad you made it to this page! Here's my take on aquarium plant fertlizer. This is not a cheap hobby so anywhere that you can save a bit of money helps. It's tough to avoid paying for lights, good substrate and CO2. Fertilizer is one of those areas in my 20 years of the hobby that i've learned you can save A LOT of money, especially if you are ordering online. In my opinion one of the worst things you can do is walk into your LFS or online store and buy a bottle of liquid fertilizer. Here's why
All liquid fertilizer is made from dry fertilizer. Dry fertilizer is used to make liquid fertilizer for many different applications. It's used to fertilize farmers fields, grow vegetables hydroponically, and used in home gardens. Aquarium plant fertilizer is made from the same dry fertilizer. If you are purchasing a bottle of liquid fertilizer, a large % of the cost of that bottle is water. Not the actual water itself but the shipping involved in getting that bottle to the end user. If you buying from a LFS, that cost the LFS incurred getting the fertilizer shipped to them gets past on to you. If you buy it online, this cost gets passed on to you as well in addition to the shipping you pay to get the order to you. So how much money are we talking about here? Let's take as an example my high concentrate all in one which sells for $14.99 and free shipping. I'm able to ship this anywhere in Canada for $2. If I was to mix into a bottle and ship it, the cost would go to $12-$18. Adding water adds at least 50% to retail cost of the item for the consumer.
This is the reason i only sell dry fertilizer. The amount of money you can save depends on how much research you want to put into it. Back when i was getting started there was one website https://www.thekrib.com/ that dealt with aquarium fertilizer and how to mix it. Now it's so easy! There is so much information available. In the above example my all in one sells for $14.99 shipped. I've seen others online sell for $25.99 plus shipping (mine is very similar in composition). If you wanted to save even more, you could buy the individual fertilizer components and mix them yourself!.