About 2 weeks ago I started to dose purple up in place of my 2 part. My corals have been looking pretty 'so-so' the last few months. Since I started the purple up, the colors, polyp extension, and new growth on all my sps has me a believer. I know a lot of people think this stuff is a joke....it aint. I wish Id started using it in the beginning. Its got me excited about the tank again. The improvement in color alone is amazing.
The problem is not that the product "doesn't work" as some would have you believe, the problem is that it is simply an expensive source of ionic calcium, a few trace elements (strontium, iodine), magnesium, and ground up aragonite (which is largely useless). It really doesn't do anything "magic" or "wonderful" any more than a quality 2 part, kalk, and/or water changes with a well balanced salt mix. Carib Sea also states that Purple Up increase carbonate alkalinity, although it doesn't specify the actual amount that it adds. There are multiple reasons why Purple Up might have shown more results than your previous method; maybe the alkalinity was too high, maybe water changes were insufficiently performed.
I happen to be very bored, so I checked out some prices from marine depot for a reference value. So here's my math (which is by no means an absolute statement, just an indicator of how context is important while considering prices):
Purple Up
1 gallon = 3.78 L = 3780 mL which sells for $137.00
3780 mL/5 mL per dose = 756 doses
756 dose x 50 gallons per dose = 37 800 gallons treated
ESV B-Ionic
1 gallon each Ca and Alk = 3780 mL which sells for $29.99
3780 mL/1mL per dose = 3780 doses
3780 doses x 4 gallons per dose = 15 120 gallons treated
The Comparison
ESV treats 15 120 gallons for $29.99
Purple Up treats 37 800 gallons for $137.00
The ratio between 37 800 gallons/15 120 gallons = 2.5
If this ratio is applied to the cost,
$29.99 x 2.5 = $75.98
To Summarize
It would cost $137.00 to use purple up to treat 37 800 gallons, and it would cost $75.98 to use ESV B-Ionic to treat 37 800 gallons.
With this significant difference in price (~55% difference actually), paired with the fact that Purple Up doesn't add anything that isn't replenished by regular water changes (which I'm assuming are being employed in both the ESV and Purple Up scenarios) one cannot logically conclude that Purple Up is a cost-effective method to maintain calcium levels. Also, I feel I should note that I gave purple up the benefit of the doubt in the aspect of carbonate alkalinity; if it so happens that the amount of carbonate it supposedly supplies is insufficient, one would have to purchase another product to supplement alkalinity, further increasing the cost of that method. Finally, I used ESV B-Ionic as an example of an alternative 2 part supplement, but it should also be noted that there are other equally effective supplements, at even LOWER cost than B-Ionic, such as Randy's two part recipes.
I would like to finish by saying I don't mean to rain on your parade. I'm not attempting to sway readers one way or the other. I really was just curious and bored, and I thought I would present my findings for informative purposes, and to spark discussion. If anyone notices any flaws with my reasoning I'm more than willing to admit error.
