I spent a small portion of the weekend running some tests using my tap water and distilled water in otherwise identical batches, as Edward suggested.

So far, findings are rather inconclusive. I was hoping for a conclusive "calcium rich hard water is the cause of sludging" indication, but have instead found what might, with further testing, turn out to be the opposite. Hopes aside, I'll continue my testing to the best of my abilities to fully prove or disprove my hypothesis, as any result that furthers our knowledge is a good result!

The Recipe

I used the basic mix steps for preparation here, but Edward has suggested that the quickest mix method is likely the most widely used method. I will be using that method in future tests.

  • 1L of water (separate samples using tap and distilled)
  • 1.5 grams Guar Gum (Bob's Red Mill)
  • 15 mL Glycerine, USP
  • 2 grams baking powder (Magic Baking Powder)
  • 40 mL Dawn Professional Detergent - Manual Pot and Pan

Initial Measurements

I took two samples of water, tap and distilled aside from the test samples, and using a standard pool / spa test strip, measured the approximate pH, Alkalinity, and Total Hardness. I will re-perform these tests once again when more accurate equipment is available (digital pH meter w/ buffering solution, water hardnes testing kit).

Sludge experiment1 4 stripMeasurement

Separate samples for pH, Alkalinity, and Total Hardness strip testing. Note the use of my best 'lab glass' a.k.a Scotch nosing glasses. No alcohol was consumed within the duration of these tests, and the glasses were prepared to spec with tap+detergent wash and distilled double rinse as well.

Tap Water Distilled Water
pH Range 7.8-8.4   (closer to 8.4) 6.2-6.8
Total Hardness 250 - 450 ppm 0 - 25 ppm
Alkalinity 180 - 240 ppm 0 - 40 ppm

Note: These value ranges are provided without testing the strips against a known buffer. When a known buffer becomes available, the values will be adjusted.



I've followed the procedure described in my previous blog post: Hard Water Experimentation, with one small change - instead of machine washing the equipment, which may have added confounding variables to the tests (i.e. introducing trace amounts of new detergents, drying agents, etc. to the mix), I hand-washed the equipment using the detergent to be used in the final solution and tap water, and then rinsed thoroughly with distilled water. I let the equipment air dry and then repeated the distilled water rinse + air dry one more time.

Sludge experiement1 1 washing ingredients

Washing + Ingredients


I then labelled the storage vessels CA: 100% Tap or CB: 100% Distilled,  and the rest to denote usage for tap and distilled use only (note: the C is for control in these labels. I originally planned to use these samples as controls for further experiments, but will likely have to re-prepare them for those experiments, as discuessed further below)

Sludge experiment1 2 labelling

Labelling Equipment

Mixing it Up


1L of water was measured out for each sample.

Sludge experiment1 3 measuring

1L of Tap Water and 1L of Distilled water

250 mL of water from each sample was poured into a microwavable container in preparation for hydration.

Sludge experiment1 5 hydration 1

250 mL poured into labeled microwavable containers

Creating the Guar Slurry

1.5 g of Bob's Red Mill Guar Gum was measured by weight and added to the final storage vessel.

Sludge experiment1 5 hydration 2

1.5 g guar in each vessel

Each sample was slurried with 15mL (1 tbsp) of Glycerine, USP. (note: the forks were washed with tap+detergent and double rinsed with distilled as well, and when removed, they were placed in the lid for the corresponding container so as to avoid cross-contamination).

Sludge experiment1 5 hydration 4

Slurry of guar and 15mL glycerine

Hydrating the Guar

Heating the Water

250 mL of each water sample was microwaved until near boiling. (I removed the labels to avoid microwaving the glue on them. I put the label on the microwave door to make sure I could keep track of which sample was being used.) Each sample was heated for 3 minutes in 1 minute intervals, until bubbling was noted.

Sludge experiment1 5 hydration 3

Microwaving 250mL of water

First Hydration Phase

Unfortunately, I missed taking photos here due to the urgency of stirring / timing, but managed to get this shot before starting - safety first!! 

Sludge experiment1 5 hydration 5

Safety First!

The first 250 mL of water (tap) was heated for 3 minutes and removed from the microwave until bubbling, and the second 250 mL of distilled was placed into the microwave and started for 3 minutes. This served as a timer for the first hydration step of sample CA: 100% Tap. The heated tap water was added to the corresponding vessel and stirred vigorously for between 2 and 3 minutes until the microwave stopped. I added the remaining 750 mL of tap water to the vessel and stirred thoroughly, then repeated the steps for sample CB: 100% Distilled. (I ended up microwaving the distilled water for an additional 20 seconds prior to adding it the guar to bring it back up to bubbling. I wanted to ensure that the initial temperature of water added to slurry was as close as possible.) While vigorously stirring the 250 mL of distilled water into the guar slurry in its vessel with my right hand, I kept stirring the tap water sample with my left, to ensure proper hydration, for 3 minutes. After adding the remaing distilled water to the hydrated distlilled sample, I stopped stirring the tap water sample and stirred the distilled for roughly 2-3 minutes, to ensure equal stirring in both batches.

Second Hydration Phase

Slude experiment1 5 hydration 6

The prepared guar solutions side by side.

The samples were stirred over the course of another 20-30 minutes at 2 minute intervals for 30 seconds at a time, and were stirred an equal number of times per sample. Note the coloration difference in the two samples - this wasn't apparent in the water before the guar solution was prepared. The cause of this color difference is not currently understood, but I have some ideas, presented in a follow up post: Tap vs. Distilled: Round 1.a (a as in ARG!)

Adding the Detergent

After 20-30 minutes of regular stirring, the detergent was added and gently stirred into the mix.

Sludge experiment1 6 detergent

After addition of the detergent.

Adding the Baking Powder

Once the detergent was stirred in, 2 grams of baking powder was added to each sample and stirred until evenly dissolved.

Sludge experiment1 7 baking powder

Baking Poweder Added

Guar Juice Completed / Observations

The completed guar juice was sealed up,

Sludge experiment1 8 closedUp

Sealed samples

 and placed in a cool, dry spot to sit for observation.
Time (approximate) Time (elapsed since mixing) Photo / Observations

7:00 pm

July 11

10 Minutes
Sludge experiment1 8 complete 1
Notes: Already, a distinct amount of sludge has formed at the bottom of the container prepared with distilled water. Only a small amount of sludge is apparent in the tap water container.

8:00 pm

July 11

1 Hour 10 Minutes
8 complete 2
Notes: It's hard to see in the photo, but the sludge in our Tap water sample has increased slightly. Increased sludge in the distilled sample as well.

9:00 pm

July 11

2 Hours 10 Minutes
8 complete 3
Notes: Another minor increase in sludge for the tap, with an apparently reduced increase for the distilled sample.

9:00 pm (Alternate View)

July 11

2 Hours 10 Minutes
Sludge experiment1 8 complete 3 a
Notes: Alternate view of the previous shot - jars turned slightly. At this point, I decided to run a parallel verification of my hydration technique alongisde this test. You'll see two new jars in the following shots, but they'll be discussed in the follow up: Tap vs. Distilled: Round 1.a (a as in ARG!)

9:30 pm

July 11

2 Hours 40 Minutes
Sludge experiment1 complete 5

11:30 pm

July 11

4 Hours 40 Minutes
Sludge experiment1 complete 7

2:00 am

July 12

7 Hours 10 Minutes
Sludge experiment1 complete 8

7:45 am

July 12

12 Hours 55 Minutes
Sludge experiment1 complete 11

7:00 am

July 13

35 Hours 40 Minutes
Sludge experiment1 complete 12

9:45 pm

July 13

50 Hours 25 Minutes
Sludge experiment1 complete 13

9:45 pm

July 13

50 Hours 25 Minutes
Sludge experiment1 sludge close
Notes: Close up of sludge / sediment / gel in CA: 100% Tap. Note the 'hill' of gel / sediment / sludge.

Immediate findings: Frustration

The observations seemed to indicate that either a) the formation of sludge occurred more rapidly in distilled water than in my tap water, or b) there was inconsistency between the hydration of the guar in these batches. Discouraged, but determined to figure out this sludging issue, I decided to continue on with a set of tests on hydration (more to verify that I could hydrate guar properly), found here: Tap vs. Distilled: Round 1.a (a as in ARG!). You can see the additional test jars in several of the shots above.

More Observations: Confusion..?

After around 9pm the first night, or around 2 hours after mixing, there wasn't significant change in sludge/sediment/gel volume. The height of the 'hill' may have increased slightly during that time.

Edward has confirmed that the gel I am seeing in my mixed samples does not look like the sludge he is used to. We're following up in Tap vs. Distilled: Round 1.a (a as in ARG!) to verify the gel substance without the addition of baking powder and detergent in an effort to ascertain what this might be.

As per Edward's suggestion, I shook both sample solutions to study the behavior of this gel a bit further.

Shaking CA: 100% Tap

Guar Based Bubble Solution - Sludge experiment 1 - Shaking Tap Water Solution

Guar Based Bubble Solution - Sludge experiment 1 - Shaking Tap Water Solution

Guar Based Bubble Solution - Sludge experiment 1 - Shaking Tap Water Solution (2)

Guar Based Bubble Solution - Sludge experiment 1 - Shaking Tap Water Solution (2)

Shaking CB: 100% Distilled

Guar Based Bubble Solution - Sludge experiment 1 - Shaking Distilled Water Solution

Guar Based Bubble Solution - Sludge experiment 1 - Shaking Distilled Water Solution

Onward and Upward

More to come.

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