Struggling with PH

[wayneb64]

I have been trying to control algae in my aquarium so I have tried a few times to add some Ottos, but only two of five have survived. I read that they prefer a lower PH so I have been trying to get my PH down to 7.5 or so but my tank just keeps coming back to 8.2 or higher.

I have used mostly softened water for years now but recently tried to use a lot of distilled water from the store to lower the TDS levels. I also just assembled a new RO system which after 5 stages the TDS is like 9 or 10 which seems fantastic. The problem is I just tested it and it's PH was 8.2.
The sixth stage is an Alkaline filter for taste and that was like 8.8 so I won't be using that water.

I have read that plants raise PH during the day and lower it overnight, and I have observed that but my PH still creeps up during the week after a water change. I have also read that lowering the TDS removes 'buffers' that help stabilize the PH.

My problem is I fear if I go with the RO water my PH is going to be all over the place and might spike up high like it did over my recent two week vacation. I had two sick fish when I got back which died within a day or two. The PH had spiked up to like 8.6 or higher, this was with mostly distilled water with a TDS in the 30's if I recall correctly.

One more item, I have some Fluval peat granules in my filter but they don't seem to be lowering the PH all that much.

 

[rlederer]

I always mix RO water with tap water until I get the right balance of hardness and pH. Since I am on a well, the water quality varies a bit but the pH is about 7.8. After going through the RO system I adjust the pH to about 6.8. Don't use straight RO water or your pH will go too low. I run a tap water line into the RO line and adjust the mixture with a valve. The pH will vary so you have to keep checking.

 

[wayneb64]

I just retested the RO water I had sitting in a cup for a few hours and it now measures about 7.2. I also tested a capped bottle I had drawn an hour or so ago and it was 8.0. Does fresh RO water need to 'off gas' for a while to lose PH? I don't want to deal with that every week when changing water so I am hoping when it mixes with the tank water the net will be a PH of 7.5 or so.

I also suspect my under gravel filter harbors a large stash of alkaline sediment from the years I used to have limestone rocks in the aquarium. That was great for the cichlids I used to have but the tetras I switched to were not happy.

Running only RO water might eventually leach all that sediment out but I will keep an eye on my PH.

 

[King Fisher]

The constant swings in pH is more than likely what killed your fish. It's better to have stable high pH. Fish adapt to pH.

Also, using RO removes most if not all minerals in the water so your fish over time will succumb from a lack of minerals. Much like how a human would without minerals in thier diet daily. You'd have to remineralize the water if you want to use straight RO.

Personally I would stick to just tap water if I was you and see how the fish adapt to the pH. It'll make life a lot easier and your fish may love you for it.

 

[wayneb64]

Can you be more specific about mineral needs of fish? I add plant food which contains trace elements for the plants. Something is also raising the PH beyond what the plants do with their day/night cycle, like I said above I suspect sediments in my under gravel filters. The TDS of the aquarium water was over 1000 so something sure is in there.

 

[ZxC]

100% RO water is perfectly fine.

Dose CaSO4 to yield 30ppm Ca.
Dose MgSO4 to yield 10ppm Mg.
Dose KHCO3 to yield 0.5 - 1.0 degrees of kH.

Doing this will result in a pH of roughly 7.2, a gH of roughly 7 degrees and enough kH to keep the pH stable.

Use https://rotalabutterfly.com/nutrient-calculator.php to determine how much to dose.

You pre-dose all this into a holding tank with RO water to net you the water change water you are looking for.

 

[wayneb64]

Just to be clear, I have a fresh water tank and the calcium and magnesium levels can be tested/maintained with products I see that are advertised for Salt water tanks right?

 

[ZxC]

Just to be clear, I have a fresh water tank and the calcium and magnesium levels can be tested/maintained with products I see that are advertised for Salt water tanks right?

CaSO4 for Ca
MgSO4 for Mg

https://greenleafaquariums.com/aquarium-fertilizers-supplements/magnesium-sulfate.html

https://greenleafaquariums.com/products/calcium-sulfate-caso4-1-lb.html

https://www.amazon.com/KEEGH-High-P...s=gram+scale&qid=1559846456&s=gateway&sr=8-24

 

[wayneb64]

I have been using stage 5 RO water as it has the lowest TDS of 9 or 10, but looking at the sixth filter stage I wonder if everything in it is all good and maybe all I need:

"Improves the taste of RO water by adding back minerals such as ionized calcium, magnesium, sodium, and potassium ions"

"Includes high-quality 3-layer Alkaline mineralization filter cartridge with Mineral Stone, Calcite, and Corosex"

"Increases the pH level by 0.5-1.2, which helps minimize the fluctuations of your body's pH"

The PH of this sixth stage was crazy purple, like 8.6 or higher so I didn't think it was a good idea but maybe a gallon or two of that for a 8-10 gallon change might be a good think right?

 

[wayneb64]

Turns out my stage 6 RO filter does not really add any measurable Mg or Ca. I have started adding Mg and Ca in "5 gallon" doses, meaning I add enough MgSO4 (2g) and CaSO4 (2.5g) to bring 5 gallons to 10 ppm and 30 ppm respectively.

The problem is after adding 15 gallons worth of them to my 30 gallon (really more like 25 subtracting rocks and gravel) I see no measurable affect to Mg levels. (My test kit starts at blue.) My Ca level is between one and two drops so between 20 and 40 ppm.

Should I just assume Mg is fine if Ca is fine since I added a correct ration of each? Does either 'decay' over time by plant or fish usage? I know aquarium salt only needs replacement with water change, are Ca/Mg the same or do I need to monitor them?

My GH is quite high, the water feels hard, and my TDS is at 670 (it was only 350 or so before adding the last '5 gallon' dose of Mg/Ca and two 5 gallon' doses of aquarium salt.

I have read and not seen clear agreement, is Aquarium Salt needed or not? It certainly had a large affect on TDS, is 670 to high?

It seems the more I learn the more confused I get on what is best for my aquarium.

(PH is stable around 7.2-7.4 and I FINALLY got my Phosphates down to seemingly unmeasurable. Also zero ammonia, nitrite, or nitrate. Mh Kh is about 2 after adding two '5 gallon' doses of KHCO3)

Do I even need to change water if nitrate stays zero?

 

[BBradbury]

Hello Wayne...

I don't think you need all the "stuff" you're putting into the water. Most fish you get at the pet stores will be fine in the vast majority of public water supplies. I don't think you need to worry about the pH, hardness or any of the chemistry stuff. What if you just set up your tank, treated the tap water, put in some hardy floating plants like Hornwort, Anacharis and a bottom plant like Anubias and allowed the tank to run for a few days? Then, get a hardy fish species like Platys or White Cloud Minnows and acclimate them properly and see how they do? It seems to me, you're making the water keeping hobby too complicated.

B

 

[wayneb64]

My 'tap' water is softened water which means the Ca and Mg is removed. I have been running with mostly that water for quite a while and I am tired of having to clean algae (or some nasty black stuff if I kill the algae) every week off of everything in the tank. (I have a lot of live and fake plants.) I like a 'happy' clean tank. I tried to buy some Ottos to help with the algae but they did not do well in the high PH water I had. I have also learned what causes the algae overgrowth and finally got my phosphates under control and the algae seems much reduced this week.

I was sick of my old lousy RO filter and now have a really nice one that can crank out lots of pure RO water. I like knowing what's in the water and I want my fish and plants as happy as I can make them. That makes me happy. My delusion is that I can get this 'dialed' in and spend far less time and have a happier aquarium.

 

[ZxC]

Okay... Lots going on here. Per 5 gallon pail of 100% RO water:

0.960 grams KHCO3 = 0.5 degrees kH
2.140 grams CaSO4 = ~30ppm Ca
2.110 grams MgSO4 = ~10ppm Mg

You add this to your incoming water, fully dissolved. You do not continue to ad this to your tank water. Dose it every tome into your incoming RO water each water change.

PO4 does not cause algae alone. Several factors cause algae, the leading cause being too much light, inconsistent CO2 levels, and too many organics in the tank / water. I dose my tank up to 8ppm PO4 on purpose every week. No algae to speak of.

Stop dosing the salt, why are you dosing it? It is increasing your TDS.

After the gH and kH boost of your RO water, you should be around 275ppm of TDS. The tank shouldn't reach over 300ppm by the time you are ready for a water change.

Also, you have live plants so having NO3 = 0 and PO4 = 0 is bad. Plants need these nutrients in large quantities to be healthy. Unhealthy plants cause algae, happy, thriving plants drive algae away.

 

[wayneb64]

My fish load is lower than normal, usually it's overloaded so I am guessing my plants are consuming all of the nitrates. I was going to add more fish once I got my water stabilized a bit. I do regret adding the salt back in the mix, I thought it's benefits were needed as I read many people who think it's good for the fish. It will get water changed out over time.

I guess I got the math wrong but I was pretty close with the mineral dosages. The water does seem really hard to me. What is a good target kH as I can measure that fairly well.

I have no idea how to stabilize my CO2, I don't think I want to get into CO2 injection. My lights are pretty bright but I have reduced the 'day' time a lot. I also have a blue light time for several hours before true night. Currently 10+ day, 4+ blue, 8+ night.

 

[ZxC]

Lights on for a max 8 hours per day if you are fighting algae.

0.5 degrees of kH is enough to keep a stable pH.

Salt is toxic to plants, unhealthy plants are inviting to algae. The cycle continues.

Dose some Metricide14 or Seachem Flourish Excel (use Excel at the "After water change" rater DAILY)

 

[wayneb64]

I am already dosing twice a week with Aqueon plant food and Flourish Excel.

 

[ZxC]

I am already dosing twice a week with Aqueon plant food and Flourish Excel.

Aqueon plant food is 98.5% deionized water - The only thing I can see in it that might help is a small amount (0.12% Iron) but it is only stable up to a pH of 6.5 and then it starts to precipitate out and plants can't use it.

Excel needs dosed daily for it's benefits. Dose the "after water change" rate daily.

What is your water change schedule like? % changed and amount per week.

 

[wayneb64]

My regular schedule is once a week, 8-10 gallons of a 30 long which has probably 5 gallons or so of rocks and gravel.

I have not got back to that schedule yet, I have been doing several extra water change days trying to get dialed in with the correct 'mix'. Did one yesterday and I will be doing another today and tomorrow to wean out the salt I wish I had not added. Current TDS is just over 450. I did add a bunch of little fish yesterday so my nitrate levels will hopefully come up off of zero once I stop doing so many water changes.

I also dose my house plants with some of the plant food water and they certainly seemed to appreciate it.