Tropical Fish Keeping banner

Low pH and Alkalinity.

11K views 31 replies 5 participants last post by  HardCory 
#1 ·
I'll get right to the point. I did a water change and gave it a few hours before checking my water parameters. Even though I have a FOWLR, I admit that I made the water a little on the light side. It's usually around 1.022 or 23. My Nitrates are high (noted) and that bothers me too (obviously). Anywhoozle...my levels are normally better than that (I've always struggled with Nitrates) and I'm just confused. I've recently started adding supplements for calcium and what not to get it better for a reef tank down the road. I added Marine buffer to help the pH but I want to know what could have caused a decrease in my GH and pH while giving my Nitrates a boost? Below is everything I can check for. Thanks!

Temperature: 89.0 F
pH: 7.8
Salinity: 1.019 SG
Alkalinity: 125.3 meq/l
Calcium: 360 ppm
Ammonia: 0 mg/l
Nitrate: 10 mg/l
Phosphate: 0 mg/l
Nitrite: 0 mg/l
 
#2 ·
Is that a mistype on your temp? 89? That seems high. Salinity seems low too, but you said you like it on the low side. I personally keep my sg at 1.025. Your pH is low, how big of a water change did you do? Did you add pH buffer to your water that was used for the change? How much live rock do you have?

You did just add a skimmer to your set up, so any organic acids in the water are just starting to get pulled from the water. These organic acids can eat up calcium in the aquarium, and drop alkalinity. This will ultimately result in a pH swing. What was the result of these tests last week? Last month? Is this a new problem, or has it been reoccuring?

The nitrates aren't a huge problem as of now, and should start to subside with running a skimmer for a few weeks. How deep is your sand bed? A 4-6" sandbed will also help in nitrate reduction, to complement a lot of live rock.
 
#5 ·
You did just add a skimmer to your set up, so any organic acids in the water are just starting to get pulled from the water. These organic acids can eat up calcium in the aquarium, and drop alkalinity.
The following point is nitpicky and irrelevant to this discussion, but I want to make a slight correction to ensure no confusion in future discussions.

Organic acids cause carbonates to be removed from the buffer system, neutralizing the acid. Calcium is a major element which forms a calcium carbonate buffering ion. The impact of organics on calcium is an indirect relationship, but the presence of organics makes the maintaining of steady calcium levels more difficult, because the calcium replenishes the buffering ion that is lost to the acid.

I'm sure that is clear as mud, because it makes my head spin.
 
#3 ·
89 isn't a typo. I've been throwing in bottles of frozen water to lower the temp. It's always been an issue in the summer. As for the water change, I only did a 7 gallon change. The buffer was added a few hours after the water change. Is there anything you can recomend?
 
#4 ·
Did you test the water immediately prior to the water change? Probably not, so when was the last time you tested the water? How much of a drop in pH are you seeing? Exactly what time of day were both tests taken?
 
#8 ·
I love the signature line Cory. Very nice. About 10 years ago a new radio station came to Louisville. For 30 consecutive days they played non-stop Van Halen, commercial free, as a countdown for their first day on the air. They opened on day 1 with ACDC "For Those About to Rock". ACDC will be here in Louisville on October 6.

On the subject of pH, how long did you allow the salt water to mix prior to using it in the aquarium?
 
#9 ·
Pasfur, could the temperature play a larger role than we were considering? Calcium is more likely to precipitate at a higher temperature. If the calcium starts to precipitate (as it does on our heaters), than the carbonate is locked up in the precipitation of the calcium carbonate. Bicarbonate is naturally more acidic (or more accurately, less basic) than the carbonate ions, and this could cause a shift in pH. Since Hardcory had a large temp swing in the past few days, I believe that these readings are a direct result of that rise.
 
#14 ·
Tap unfortunatly because the only store that sold RO doesn't do it any more. And cince I live in apartments I can't get a unit either. But I havn't used RO in almost a year. Not that it's a good thing but I don't think it would suddenly change like that. By the by, my pH is back to 8.2 thanks to the buffer (assumingly).
 
#18 ·
I am just reading this thread and nodding my head up and down. I have nothing to add. The line of questioning here is right on course.

Ok, maybe I have something to add. Even if the temperature has been high for an extended period, the addition of Calcium chloride could have increased calcium levels to cause a precipitation, especially given that calcium precipitates more readily at higher temperatures. (Wake - this is new to me. I believe you, but do you have a link? Knowledge is power!)

However, if you did in fact precipitate calcium, I believe it would have been visible. I have seen this occur in person, and it is very difficult to mistake for anything else. It literally looks like it is snowing inside the aquarium, unless of course it is just a small isolated precipitate on the heater.

Also, by testing pH in the evening, you are getting a higher reading than you would have received in the morning. This worries me, because your pH had a low point of below 7.8. I'm glad you caught this and are dosing accordingly.

Great questions on borate and magnesium. Some research is needed on this (google?), because if these concentrations are higher than the natural ratios in seawater, then the alkalinity test kit will give you a false low reading, with the result based on the assumption that magnesium, borate, and calcium are in balance, and the test actually testing for calcium buffering ions. So, if Calcium is 440 ppm and the other levels are unnaturally high, then calcium is more likely to precipitate, causing the rapid pH drop. :) Fun stuff. Ironically, many sea salts add additional borate and magnesium for additional buffering capacity, on the assumption that the fishkeeper will not test for alkalinity as they should. The additional buffering helps between water changes.
 
#19 ·
I read it in a Randy Holmes-Farley article. It's about three quarters of the way down. It kinda makes sense to me as redox is accelerated by both light and heat. I would then consider that calcium and carbonate would go through a reduction as the temp rises, and bicarbonate would become predominate. Of course the swing in pH that Hardcory experienced would probably have been caused by either a large temp jump, or a prolonged temperature change.

This hobby makes me think that I probably should've majored in Chemistry instead of Biology.
 
#20 ·
Farly is the best. I have several of his articles saved in my favorite links. Alkalinity is such a complicated subject it is no wonder that the LFS generally just skip the entire discussion. I find myself not worrying about the why and instead just focusing on the what to do.
 
#22 ·
How are the inhabitants doing? Have they showed any signs of stress over the past couple of days?

Can you re-test everything and post the results? I would like to know where all the other levels are, including: temperature, salinity, Calcium, Nitrates, and pH. And let me know if the lights are on and how long they have been on when the tests were taken. Thanks.
 
#23 ·
Lights have been on since 9:30AM and this is what I've got so far...

Temp: 87F
Salinity: 1.020
Calcium: 400
Nitrates: 10 (Maybe 15)
pH: 8.2 (Maybe 8.3)

I'm using API kits. Both the NO3 and pH are on th dark sides so the "maybes" are inbetween 2 colors.
As for my fish, everyoy looks good with the exception of y Hippo having ich.
 
#25 ·
The other thing is that 87 is a high temperature for ich to survive. I have heard of ich treatments that involve reducing your salinity and raising your temperature. I don't know if you're trying this, but I suggest reading up on it first. I myself have never tried it; I personally use garlic and do small feedings, multiple times a day.
 
#26 ·
Yeah I'm using a hydrometer. As for the ich, I agree with your approach. About the only thing I used to do were fresh water dips but since I don't have a freshwater tank anymore I just stick to garlic and Kent Marine's Rx-P. It works REALLy well IMO. Thanks for the link by the way!
 
#28 ·
Next time you should start a new topic for questions unrelated to the existing topic. However, I use the Red Sea Marine Lab test kit. I test primarily for alkalinity, calcium, pH, and Nitrate.
 
#29 ·
the temp being higher will increase the life cycle of the ich but having high temperatures also has downfalls. metabolisms are faster, more oxygen gets used but ontop of that warmer water doesnt hold disolved oxygen as well as cooler waters, and so forth.
i would get atleast a fan blowing over your lights or sump or if possible a chiller. if your going the chiller route try looking for a used one first on craigslist or a local reefing club.
what are you feeding the tang and how often? i would also use selcon with the garlic and a squirt of live black worms would be beneficial but def. not to many or to often esp since tangs diet mostly consists of mixed algaes.
 
#30 ·
I have dried seaweed (red & green) and she loves scallops/clams. Went after some black worms too. Everything is frozen. Once I get a few bucks I'm going to grab something that is more specifically designed for tangs.
 
#31 ·
If the Tangs are not eating the seaweed, try this. Fold the sheet in half and attach it to a lettuce clip. Then cut strips into the seaweed so that it sways in the water current. Tangs usually find this irresistible.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top