I have not seen any posts about Rapid Grow Fertilizer besides one where @bigbadjon
referenced using it last year.
I thought I would share what information I have about the product in case others come looking for information.
It is sold as a dry mix fertilizer with instructions to mix into a liquid fertilizer for short term storage and dosing. It is made and packaged by Greg Sage of Select Aquatics. He is known mostly for his livebearers and plecos and is generally just a knowledgeable and kind person. Here is the product page: Rapid Grow aquarium Plant Fertilizer
The fertilizer is invertebrate safe, which was critical for my usage. Greg does not publish the exact breakdown, but will readily answer questions via email. I asked him a few and will share the answers:
- It contains iron at .13%.
- It contains Ammoniacal and Nitrate forms of Nitrogen.
- It does not include trace elements Cobalt or Boron.
- The dosing recommendations are based on "a combination of the best concentration for plant growth with the least potential for toxic issue for fish, and was derived over three years of testing... in [his] fish room." His fish room primarily uses java moss and java fern, potted or free floating, with medium light. His website has many examples of his tanks.
I bought the fertilizer a month or two ago on a whim since I was not having much luck with Seachem (due to my own ignorance most likely). I began dosing Rapid Grow in my display tank about 2 weeks ago, so consider this a short-term review.
The fertilizer mixes nicely and the instructions make it easy to dose since it is not too concentrated in liquid form. 1.5floz or 44ml per 30 gallons of tank water per month. For my 40g I end up at about 60ml per month, or 15ml per week.
I conducted the first dose as a 15ml weekly dose. Starting in the second week, I begam auto-dosing 2.5ml per day. I also conduct ~7% daily auto water changes, so I dose right after changing water.
I don't have much experience with other fertilizer options besides Seachem, so this analysis is somewhat in a vacuum.
My tank is a 40g with a Fluval Plant 3 and injected CO2 (at low levels, 10-15ppm). I have some stems, moss, monte carlo, a buce, some tripartita japan, scarlet temple, and a few others. EcoComplete substrate. I also have API root tabs under the densely planted areas.
Prior to dosing any ferts, the plants all grew slowly. The moss seemed to be eating up many of the nutrients since there is a large amount of it and it catches a lot of CO2 bubbles. The monte carlo didn't spread at all in the weeks prior to dosing. Almost immediately after the initial dose, the monte carlo began spreading. It has seen considerable growth by my standards since dosing began. The red plants are not exhibiting very good coloration, but that is to be expected with the low amounts of iron in the mix. I plan to supplement the dosing schedule with iron.
Some of you will have noticed that this contains ammonia per his answers. I did not get any information on how the ammonia is built in. Seachem claims that theirs is "complexed." I don't know enough water chemistry to know how that functions or if Rapid Grow is also complexed.
I will try to continue updating or answer questions, but so far so good. Here are a couple of progress pictures. I am new to growing plants so I cannot grow as fast as many here, but I am happy with how it functions for now.
Rapid Grow in the DOS system, nearest the camera:
July 21 (no dosing):
August 1 (no dosing):
August 11 (after initial dose):
It has definitely helped the moss perk up and also has allowed the monte carlo to spread a bit.