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Soft but high pH tap water

18K views 10 replies 6 participants last post by  OVT  
#1 ·
Hi all,

I am trying to figure out what my tap water is before I start dumping EI-, PMDD-, PPS- brews of ferts into my tanks. My water district reports "hardness" 108, Alkalinity 69, Ca 21, Mg 12.7, Na 63, SO4 60, K 3.3 (all in mg/L) AND pH of 8.5 (report)

Testing the tap water myself I get pH 8.8 with calibrated HANNA pHep 4 and dKH of 3 using API's reagent test kit. I tried to measure dGH multiple times with the said API kit without any success (the color never turns from orange to green regardless of how many drops of reagent I add).

I am guessing that I have "soft" water with artificially high pH (water district adding biocarbonates to protect pipes?).

I would really appreciate any recommendations/pointers/education/etc. on:
  1. how to measure GH
  2. How to achieve PH/KH/GH long-term balance (CaCO3, CaCO2, MgSo4, vinegar, pHdown, ... ?) if I target neutral pH and dGH/dKH in 4 - 7 range

Thanks a bunch

75T and 36 Corner with ~3.5w/gl Eheim 2026
22G non-name nano-knock-off with 4.35 w/gl built-in sump-type filter
all 3 100% planted
moderate fish load
 
#2 ·
Wow. Just wow. That is about perfect water for a Sulawesi shrimp tank. I know a lot of folks in the freshwater invert community who would absolutely DIE to have water like that coming out of their tap.

As for getting that water down towards more "normal" values, I'm not really sure what to say. Even a 50-50 mix of that and RO water would probably still be at a pH of around 7.5 to 8, I would think. Maybe higher. So I'm a bit at a loss regarding what to do about it.
 
#3 ·
An alkalinity of 69mg/l (assuming it is "as CaCO3" like most water reports) is a dKH of about 4. Not bad.

Total hardness of 108 mg/L is a gH of about 6. Also not too bad.

I don't know how they are getting the pH so high. gH and kH look fine to me.

In any case, the TDS of your tap water is above 300. I would be tempted to do RO just because of this.
 
#4 ·
I'm kind of jealous. I have looked through 10 years of reports in my area and they have never broken down the nutrient levels like your charts show. At least you have that to work with as a starting point. My report only lists the GH, Turbidity, flouride and levels of chlorine, copper, nitrate, lead, sodium, and sulfate. Nothing more.
 
#5 ·
The water quality report isn't always going to reflect your actual conditions. The report for my area shows I should require about 40 minutes to wash the soap from my hands basically, but my GH test require anywhere from 8 to 12 drops to see a change. I don't see Ca buildup or anything on faucets, but my water doesn't feel soft either, and I've grew up in an area with extremely soft water.

If you are going to use EI, I would dose according to the tank size based on these recommendations:

http://www.barrreport.com/showthrea...p/1800-EI-quot-light-quot-for-the-less-techical-aspects-of-the-Estimative-index

Then lower the dose over time until you see a negative result. Then bump the dose back up slightly and go with that. If you're worried about Ca/Mg deficiency, simply add a small amount of GH booster (say 1/2 tsp) with each water change. There's no real reason to attempt to get each nutrient to some accurate measurement, so long as you dose according to the high end limits. The water changes will remove any excess at the end of the week. Observation over time will allow you to trim the dosing if desirable. IMO the ferts are cheap enough I just stick to the high end dosing.

Why are you trying to reach a neutral PH, just out of curiosity?
 
#6 · (Edited)
I think you're on the right track OVT, the tap water is probably sodium hydroxide-treated to soften it, that would explain among other things, the high Sodium content.

Your pH will not be stable at over 8, already when the Co2 pressure in the water has reached equilibrium with the air the pH might be well below 8.0 After that pH will sink slower, but not stop sinking unless you buffer it.

As long as you're not going to run the tank really high tech, addition of crushed limestone, snailshells, eggshells or equivalent in small doses with some time between dosing, until you reach a nice pH should give you good hardness, in whatever scale you choose to measure.

When you've reached your target pH you can test the water with longer and longer intervals, you'll see that it'll be fairly stable, as will you're aquarium in general.

I have a tap water similar to yours, I use from 1 ppt crushed snail shells intended for calcium additive for hens, I rarely change much water, and dose ferts judging from the look of the plants, and algae if there's any.
 
#7 ·
Thank you all. I'm still puzzled why I cannot measure the GH. I'll take a water sample to my local LFS and see what they say.

I know a lot of folks in the freshwater invert community who would absolutely DIE to have water like that coming out of their tap.
WTS: water from my tap :). The idea of a 75G shrimp tank never entered my head.

Why are you trying to reach a neutral PH, just out of curiosity?
Based on my personal experiences and (mis)conceptions:
  1. Co2 levles at low hardness and high pH (ie. 1.0 mg/Q at 8.0 pH and 3 dCH)
  2. Algae "alcaline advantage" at high pH
  3. Amonia toxicity at high pH
  4. All "fish guides" I read indicat pH ranges for specific fish, with 6.5 - 7.5 pH seemingly being the norm. Same goes for plants.
  5. The pH in the 4 LFS in my area range from 6.7 to 7.8 pH. Try to add their fish to a 8.8 pH tank
  6. My interests lean towards South American biotope, tetras and Discus seem to have difficulties in my (now) 8.6 pH tanks when they were doing ok when my tap was at 7.2 pH
  7. I used to bring buckets of swords, cabomba, hygrophila, rotala, nymphea from my 7.0 pH low-tech, no-CO2 tanks to my LFS for nominal store credit (please see pics of my tanks). Now, I have difficulties keeping my plants alive

Given, I might be focusing on pH as the root of all evil for my situation :) when multiple other factors might be at work, but getting my source water under "control" seems like a logical first step to me.

I do take contractive criticism semi-graciously, so, do feel free to debunk anything and all. After all, I joined the august members of APC to learn and to share.

Cheers
 
#9 ·
Thank you all. I'm still puzzled why I cannot measure the GH. I'll take a water sample to my local LFS and see what they say.
Not uncommon, IME. I cannot explain it as I'm certainly no chemist, but I've talked to many hobbyist who were sure they could have dumped the entire bottle of test solution into the tube and not gotten a color change. I've talked to the folks at the two LFS I trust about this, as my GH is odd considering my local water quality report suggests I have soft water, but I can tell just washing my hands with soap that I don't. They have encountered samples people have brought in where they could not get a color change. I can't explain it, so I just add some GH booster and don't dwell on it.

Granted, I don't keep sensitive fish, such as discus, but there isn't as much consensus regarding their desired water parameters as some might lead you to believe. But with $100-150 fish at the juvenile level, most people aren't willing to experiment. I can't say I hold it against them.
 
#8 · (Edited)
I have high pH water as well is why I asked, and I am keeping similar plants--several varieties of hygrophila and echinodorus, both of which do well. My nymphaea micrantha puts out 2 new leaves ever week minimum. My rotala grows fast; staurogyne grows steadily. High pH is common between us, but my plants are doing well, so I wouldn't focus on it at all.

From your profile, I see you have very high light, no pressurized CO2, and your initial post suggests you haven't begun EI, as yet. This appears to be the problem to me, with what info I have to go on. If you aren't going to do pressurized CO2, you do not need the degree of lighting you have. I personally would remove 2 bulbs from the 75 gallon tank. Two of the 65W bulbs should be sufficient--aim for 1 to 1.5 w/gal with CF or t5HO lighting if no CO2 enrichment. A little higher with t8s. With the amount of lighting you have, you are pushing your plants into a very accelerated state of photosynthesis, but you aren't providing them with the other nutrients they need to maintain it, ie, CO2 and ferts. Cut the lighting back, start dosing EI, add some GH booster to cover any possible Ca/Mg deficiency so it's not an issue you have to even consider, and watch and wait.