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Green Leaf Aquariums is a leading planted aquarium brand with 20 years industry expertise in: professional lifetime aquarium CO2 systems, the finest quality aquarium plant fertilizers, thriving aquarium plants & tissue cultures, and specializing in custom hardscape design

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  • Green Leaf Aquariums, LLC
    5200 NW 43RD STREET
    SUITE 102-264
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GLA 4dKH Solution - 30ppm CO2 Analytical Standard

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4° KH or 4 dKH LAB CERTIFIED ANALYTICAL STANDARD - 118ml (4 oz) bottle

CO2 Level Indicator Fluid: 71.44ppm Alkalinity as CaCO3

* ships with / includes pipette for ease of filling drop checker with indicator fluid

4 dKH fluid is used in a CO2 drop checker as a CO2 level indicator. When combined with pH reagent, the solution color will change from blue to green when optimal CO2 of 30ppm is achieved.KH Standard / 4 dKH (lab certified analytical standard 4 dKH) is used in the drop checker to accurately measure CO2 levels in the aquarium. The KH standard / 4 dKH needs to be combined with approximately 2 - 4 drops of pH indicator in your drop checker until a strong transparent blue color is achieved.

Instructions for Use of 4 dKH in CO2 Drop Checker

Combine bromothymol blue/pH indicator reagent into 4 dKH fluid in your CO2 checker until a strong blue color is reached. Install checker on tank and wait 2 hours to observe color change/CO2 reading.

Drop Checker Color Chart of Aquarium CO2 Level

BLUE ... low level of CO2 <30ppm ... increase rate of CO2

GREEN ... proper CO2 level of 30ppm ... no action required

YELLOW ... high level of CO2 >30ppm ... decrease rate of CO2

*all color observations & CO2 adjustments require 2 hours wait period for accurate color readings.

*use 4dKH with drops of bromothymol blue/pH reagent to create DIY Indicator Fluid for CaL Aqua Labs CO2 checker glassware

4 Reviews Hide Reviews Show Reviews

  • 5
    Top Quality stuff

    Posted by Brandon Smith on 12th Feb 2020

    I use this in my DIY drop checker I made a few years ago and can honestly say this is the best 4DKH I have ever come across. It registers far more quickly than others and very accurate in its reading. You do have to add ph reagent to this, but this is what keeps this solution perfect while sitting on the shelf. You dont want reagent sitting on the shelf for 6 months or a year. You want both separate and only mix the two when your going to use it. Otherwise you need not look any further for a proper 4DKH solution for your drop checker. GLA has the goods.

  • 5
    The most accurate 4dkh on the market

    Posted by Adam Wood on 3rd Feb 2020

    I ordered this to replace my previous 4dkh I got off amazon which was some Nilocg brand. This is far superior, and I have no idea what that other stuff was but it is nowhere near as accurate and quality as this. I tested Nilocg brand and it came out to almost 5DKH! GLA 4DKH, you guessed it, spot on! I feel this is what makes it respond so quickly because after only 30 minutes of co2 being activated its starts to register color right away. The Nilocg stuff seemed to take several hours. This also comes in a large bottle format so it will last me years to come.

  • 5
    The very best 4DKH solution on the market

    Posted by Adrian Burnside on 22nd Jan 2020

    GLA 4DKH solution is and as to be the most accurate 4DKH solution I have ever tested(Hanna colorimeter) and used. I have tried every darn 4DKH solution on the market and GLA 4DKH solution is the only one that comes dead spot on 4DKH. I challenge anybody to find a more accurate solution, you wont though because I own all the brands from Amazon,Ebay and the other competitor brands. Whatever GLA is doing they are doing it correctly. This stuff has my drop checker reregistering color change within 15-25 minutes of my co2 system powering on.

  • 5
    The absolute best!

    Posted by Dave Overhultz on 22nd Dec 2019

    Im not sure how to say this but all I can say is that GLA 4DKH is in fact the best drop checker solution on the market. Its the real deal and its accuracy is unmatched by anything else I have used, and Ive used all of them. The response time on this 4DKH is literally twice as fast compared to anything I have used. Dont hesitate to use this in your drop checker because as far as Im concerned anything else you look at is garbage and waste of money. This stuff is the best!

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