Plants, Swinging pH & Water Changes
I've had lots of problems with my newly planted tanks. Bottom line is that I had lots of dead organics, too much algea, and I'm holding bad bulbs responsible. I just replaced all my tanks w/6500kh flourescents and hoping for the best.
In the meantime, I lost a betta (almost 2) due to a swing in my pH during a water change. Obivously my pH had dropped due to the dead organics and in my lack of knowledge, I was oblivious. My tap is 8.5 and the tank water was 8.0. Due to my ignorance I'm on a water chemistry quest for understanding. With that said, I now have 4 liglhtly planted tanks & one without plants at all (they all died). I purchased a KH and GH test kit and my parameters are listed below.
Can you guys help me with water changes?? How do I perform a water change without causing a pH swing in the tank? Normally I do 50% weekly changes. I was told to try mixing in spring water, but I know that spring water doesn't contain any of the essential minerals the fish need. Also, I'm aware that bettas are soft water fish but I know they can thrive at higher pH levels as long as it's stable. All the tanks are cycled and all ammonia's & nitrites are 0 with the nitrates at 10ppm.
Tap - (not degassed)
10 gal Tank 1 -
10 gal Tank 2-
25 gal Tank 3-
10 gal Tank 4-
10 gal Tank 5-
Any help would be appreciated. I'm 3 days late on my weekly water change.
I am no expert, nor did I stay at a Holiday Inn last night but personally 50% water changes weekly is a little too much. What type of filter are you running? My suggestion would be now that the plants are out is to do frequent 20% water changes, maybe once every 4 days or so for a few weeks then cut down to once a week. I would not try to alter the PH at all, it is what it is, the more chemicals you add the worse it will be. Let the tank restabilize itself by doing gradual water changes, the fish will aclimate slowly. Worst thing to do is a massive water change that causes a quick large PH change. Drift wood will help slowly lower the PH and soften the water.
In those numbers, I am surprised by the varying GH in the tanks. The tap water GH normally does not change; it should not be higher in a fish tank unless there is something calcareous in that tank. This would be the substrate and/or rocks. What substrates do you have, and are there any rocks in the tanks? Or are you adding any substance?
Hi Byron - I've listed below what I currently have in the tanks. I don't add any chemicals or products to the water besides Flourish. Please note that I'm ready to just start over. I've had such a hard time and I feel like I didn't take my planted experience serious enough. I really love the plants and I know my fish do too. But with all this plant death and water variations I've created more work and stress for myself than I meant to. Your direction is appreciated:
All tanks (with the exception of #3) contain bettas and the filters are baffled. However, none of my filters contain charcoal - only filter floss to house bacteria.
Tanks 1&2 - These tanks are only 1 month old. Substrate is a natural style gravel. I didn't realize when I set up the tanks that the substrate bag stated it could "alter the pH". I posted another thread regarding this issue because the gravel actually clouded up my water in Tank 1 because I didn't rinse it enough. No other rocks added.
Tank 3 - This is my longest standing tank. Going on 2 years. I believe the gravel was coated. However, it has a pretty big 'wonder rock' right in the middle. This tank houses praecox & gobies - filter is not baffled.
Tanks 4 & 5 - These tanks are 7 months old. Both contain regular gravel that I don't believe is coated. The bags stated they would not alter the pH. No other rocks included. However, tank #5 recently got infested with cyanobacteria. I removed both fish, rinsed off the resin decorations and turned up the filter. So far it hasn't returned. Those fish have not been returned yet.
I have an additional 4 tanks, but none of these contain substrate, plants or rocks. They're bare until I can figure out what I'm doing wrong.
Some general comments. It is normal to have a higher pH in new tanks. Once the biology settles, it will lower. But hardness is determined by the mineral content of the water. Adding calcium and magnesium (primarily) will raise hardness and corresponding pH, while diluting the water with pure water (rainwater, distilled, RO) will lower hardness and allow the pH to drop. Of course, there are other minerals that can raise hardness but not as much as calcium/magnesium.
The substrate that "could alter pH" may be the issue in that tank. But the others puzzle me. Your GH numbers are very precise, down to decimal points...what test are you using?
It's API's GH&KH Test Kit. The precise numbers are from their "Conversion Chart" they include with the kit. It's actually based on how many drops it takes of the reagent to turn the test tube color. My apologies if this is something you already understand. I'm happy to re-do the tests to see if I get different results. Here's a link of the conversion chart from their instruction paper:
Tap: 5 drops [= 5 dGH]
Tank 1: 8
Tank 2: 6
Tank 3: 4
Tank 4: 8
Tank 5: 6
This still puzzles me. Tank 3 might perhaps be 5, same as tap; I know how difficult is it to ascertain when orange becomes green, I usually go one drop further to be sure. Assuming this is the same, that means that something in the other tanks is raising GH. The presence or absence of plants is not going to do this. The substrate in the one may be the cause there; the rock in the other perhaps.
The pH though is relatively the same in all tanks, and lower than the tap which is what I would expect. The GH and KH is not high, so over time the natural biological processes should (and appear to be) lower the pH.
To answer your initial question about the pH fluctuation with a water change: to be honest, I would forget about the GH/KH. The pH is stable around 8.0 and if the tap is 8.5 the fluctuation in pH caused by the water change will not be an issue. My tanks vary by .4 to .5 every water change and I've never had an issue in 10 years. My tanks run at pH 6 with some at 5, and the tap pH is 7.0 or 7.2 and I change half the tanks weekly and the variation is maybe .5 max. The reason is that the tank's biology settles in time and with the plants and buildup of organics and bacteria in the substrate, it will resist changes. Even though the GH/KH may be low [mine are < 1 dGH and KH except in the tanks that I raise to 3 dGH with dolomite/aragonite] the biology will tend to be stable.
In your case, with the slightly higher hardness, I would change 1/3 max. Test pH prior to the next water change, and then about 2 hours after. Post the numbers and I'll review.
Byron you're a life saver. Thank you so much. I've felt so defeated over my tanks! I'll test my pH's as noted and I'll post numbers. Thanks again!
(I love your signature . . . how true it is!)
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