Hi all,

Tested my water in the 55 gal. Nitrate 10, nitrite 0, ammonia 0, and ph below 6.2. The color in the test tube was lighter than 6.2 which is the lowest on the chart. The means my water is very acidic. Is that a bad thing?

Yes, generally speaking, it is a bad thing. You are close to a pH crash and the nitrogen cycle is only 10% effective at a pH of 6.

Do you have a KH test kit? You need to adjust your carbonate hardness (KH) which acts as buffer to pH swings. I would suggest you get one soon and verify the KH result.

Also test your source water. If it is acidic to start with, it will make it harder for you to control your tank's pH.

In the mean time, I would add 1 teaspoon of baking soda to the tank every 24 hrs for the next few days. Pre-dissolve the BS in a cup of tank water and make sure it is mixed in the tank well. Retest your pH and KH 1 hour after the BS is added. That should raise your KH by ~20ppm per day. You don't want to rush this as the BS can cause your pH to leap up >8 if you use it too much or too fast. You need to aim for a KH of around 100-150ppm. As you add more BS, the pH will rise but should not be a huge jump.

Hi Captk,
I have a question in the PH/KH relationship. My tank PH did crash cause by low PH and adding BS did help to recover the biobugs to convert ammonia. The ammonia level is zero and the water is back to normal. I add about 1tsp BS everyday to increase the PH. PH reading now is about 7.1 from 6.4 when it crashed. THe question is since the recommended KH is 100-150ppm, will continous addition of BS to increase the PH level will cause excessive increase in KH level? I could not find a tester for KH but I have test strips for GH which is at 50ppm.
I intend to get some crushed corals to act as a buffer next week (most lsf are closed for the Lunar New Year).

Yes, Happy Chinese New Year to you! (if you celebrate it )

Most biological process produces acid somewhere along the line. E.g. Fish exhale carbon dioxide, some of that combines with water to form carbonic acid. So the pH of a tank tends to head towards acidic if left alone with no buffering.

The relationship between KH and pH is not direct. The carbonate is there to buffer pH swings and the nitrifying bacterias also consume them. A ready source of carbonate is BS. The pH of BS is 8.4. So if you add sufficient quantity of BS to a tank of water which is neutral or alkaline then it will move the pH towards 8.3-8.4 and become stable around that level. If your source water is acidic then it will be lower than 8.4, maybe in the high 7's.

Rougly speaking, 1 teaspoon of BS in a 40 gal tank once a day will raise the KH by 20ppm. So assuming that your KH is close to zero, you would need about 7 days of treatment at that dosage (if you have an 40 gal tank) to reach a KH of around 150ppm.

If you can't get a KH test kit then keep adding 1 tsp of BS a day until your pH is mid to high 7 which is a fairly safe range for goldfish. As soon as you see a drop towards low 7, you start adding 1 tsp of BS a day until pH returns to the desired level. Still, having a KH test kit is the easier way.

I prefer crushed shell than crush coral because depending on how fine they crush the coral, it can come with a lot of fine particles and it can make the water super cloudy and coat everything with a fine dust which is hard to get rid of. Coarse crush shells are much cleaner and works just as well.

GH & KH is not directly related. GH measures the amount of dissolved minerals. You can have hard water with low KH.

Hi captk,

Thanks for answering my post.
No I don't have a kh test kit and I can't buy one right now, but will go to the store to get BS. I will test my tap water and get back to you when I get home from work. Have to go now talk to you later thanks.

Hi Captk,
Thanks for the useful information. Yes, I do celebrate Chinese New Year and thanks for the greetings

Ok I'm back from work.

I tested the water from the tap and it reads at 7.0 . I have three goldy tanks, a 55 gal., 30 gal. long, and 20 gal. high. Tested all for ph and they all read 6.2. I haven't tested for ph in months and it use to be at 7.2. Never had ph problems in the three years I have been goldfish keeping. I have the baking soda. How much do I put in the 30 and 20 gal. All help is needed thanks.

Oops, wrong thread. Deleted!

Sorry about the last post. Wrong thread.

The carbonate is consumed by the nitrifying bacteria so if there isn't a steady supply of carbonate, the KH can drop gradually over a period time and caught you unaware.

Okay, with BS, the formula I use is 1 teaspoon of BS in 45 gal will raise KH by about 20ppm. You don't really want to do more than 20-30ppm a day or the pH can jump up too fast. Slow and steady is better.

So with the 55 gal you need just over 1tsp per day. The 30 gal a bit under 1tsp and the 20 gal, half a teaspoon. Dissolve the BS in a cup of tank water first and then pour the lot in and make sure it is mixed in well.

If you don't have KH test kit then monitor the pH 1 hr after adding the BS and stop adding BS when your pH has reached mid to high 7. If the pH starts to drift downwards to low 7, start adding BS again until it comes back up.

OK, Thanks. Will let you know how everything is going.

Good luck!

Hi,

OK, I didn't put BS in the tanks yet. Instead I went to the lfs and they had the GH&KH test kit so I brought it. It is a little confusing to me I think I did it right. The test kit is the one from Aquarium Pharmaceuticals. Does anyone else have this test kit. I kept putting in drops until the solution turned bright yellow but it started out a pale yellow when the directions said it should turn blue first.

Here are my results:( KH) 55 gal. 89.5 -107.4 ppm and 30 gal. 125.3 ppm. Didn't test the 20 gal. because it is in my daughters room and she is sleep for the night. If I did something wrong please let me know. Will wait for someone to respond before adding Baking soda. Thanks

Yep, I have the same test kit.

How many drops did it take to turn from blue to bright yellow?

Oh, I just reread your post. That means that you have less than 1deg of KH! It should turn blue first if you have some carbonate in the water. It will start off pale yellow if you don't have enough to get a blue reading after the first drop. If your KH is > 1deg, it will turn blue and then from one drop to the next, it will go from blue to yellow. Quite dramatic!

That would make sense too. That is why your pH is low. You have very low KH. If you are in doubt. Just add a pinch of baking soda into a glass of water. Then use the KH test kit to test that solution. You should register a KH reading. How much will depend on how much of a pinch of BS you added.

I'm sorry, 2befree, I edited the post above quite heavily and I don't know if you would have noticed it so please reread the post above.

Hi captk,

Thanks for the explaination about the test kit. I put baking soda in the water as you suggested and it turned blue first. Amazing!

So I added the BS to all three tanks this morning. Tested the water a few hours later ( had to go out for a while) and the PH reads at 7.2 where it use to be. Yepee! Now you said I need to add BS every 24 hours. I leave home before the 24th hour tomorrow morning. Is it OK to add more BS a couple of hours early? and How long would I have to add BS?

You mentioned something about crushed shell to act as a buffer to keep ph steady, where could I get some?

Thanks. Anxiously waiting for your reply.

I'm glad you experimented with the BS. It is very important that you understand what you are doing and what are the result.

You should add the BS once a day (it doesn't have to be 24hrs exactly ) until you get a reading of ~100ppm or about 5 drops. When you reach that level, you can change to 1 dose per week until you get to ~150ppm. Stop adding the BS then. Only add more if the KH drops to ~100ppm. Your pH will gradually rise over time as well. If you don't want it to go too high, stop earlier but then you will have less KH in reserve and you need to monitor your KH/pH more regularly and be prepared to top up with BS.

You can either use crushed shell or broken pieces of coral. They are usually available at aquariums and better petshops. Make sure you rinse them well before use as they can have fine particles mixed in and can cloud your water.

Keep us posted.

One more question. Would I have to add more BS when I do water changes? I do between 30-40% once a week.

The simple answer is yes but it also depends on how much carbonate is in your water. The easiest way is to do a KH test an hour after the water change and see what the KH is. Adjust as necessary. Soon you will get a feel of the impact of water changes and can antipate the need to add more BS or leave it to the crush shells/corals.

Crushed coral/oyster shell works very well. I had the same problem and now with added crushed corals and shells, the PH is maintained at about 7.3 without adding BS for a 25% water change. Our tap water had zero KH thus causing the PH to crash and the nitrifying bacteria stops working and eventually seeing ammonia in the cycled tank.
It has been 1 week since I added the corals and the PH is very stable now. Thanks to Captk and Betty for their help. The only problem now is the nitrate level build up very fast due to the high efficiency of the nitrifying bacteria in optimum condition. I am overstocking the tank and nitrate level is at 80ppm after 5 days of water change. I think I have to perform water change every 4 days to reduce the nitrate level maintaining it below 40ppm. Any good method to digest the nitrate in the water apart from using a coil of long hose method?
Cheers.....

Hi Ranchu_man,

Other than water changes, the usual means are live plants (which works), trickle tower (low flow wet/dry filter) (works but easier if it is a pond situation), special filter media that is suppose to encourage growth of nitrAte consuming bacteria (tried it, really good at "polishing" the water but so-so with the nitrAte). Then you move onto special filters with very exotic designs and chemical additives that are closer to snake-oils.

I've talked to one person who had good luck with one of the commercial coil denitrification units. Water is slowly fed into a long coiled tube... by the time it reaches the end of the tube there's no oxygen left and a set of anaerobic bacteria convert the nitrAte into nitrogen gas. The problems with those is it's possible for it to get converted to nitrIte instead of nitrogen gas. I've been tempted to set up a DIY coil denitrification unit, but haven't yet.

There is actually one goldie person here with a planted tank who has to add nitrAtes to her tank. There's a thread on her set up over in the plants forum.

Hi RM, forgot to mention. You probably should review their diet and the amount you feed them. Don't forget that the nitrogen cycle starts from the ammonia so if you have more ammonia to convert then you nitrAte will be higher at the end. Overfeeding/rich diet will keep the ammonia high so see if you can influence the nitrAte level at the front end of the process as well as the back end.

DG, I know plants work and I always have some plants in my tank but for a heavily planted tank, what about the day/night O2-CO2 cycle and the resultant pH swing? I suppose the tank can be temperature controlled and aerated so it will reduce the threat of oxygen starvation. What are your thoughts?

I'm not sure the pH swing is anything to worry about, as long as the water has decent levels of KH. I have a bubble wand in my heavily planted goldie tank and the plants are doing fine. I also have the plant filter running on an opposite light schedule from the tank, so when one set of plants are producing CO2, the other set are producing O2. That should help keep things on an even keel.

One could use a bubble wand and add something like Fluorish Excel for a carbon source for the plants.

OK I added more BS this morning. KH is now between 143.2 - 161.1 ppm about 8 or 9 drops. PH is at 7.4 . Should I add anymore BS in the morning. Won't be able to get to pet shop for crushed shell till the end of the week. WOW! the things we go through for our fish

Yeah, that's about perfect. No need to add more. Keep testing weekly and when the KH drops to around 100ppm, start adding 1 tsp/day again until 150ppm. Well done!

I used to have some live plants in the tank but the gf keeps on munching it and it looks awful after a while. I am now using plastics thus nitrate will not be consumed at all. I agree that I am feeding the gf with high protein food 3 times a day and might be the cause of excessive nitrate. Will cut down the feed rate to twice daily.

On the denitrification system, I think it can be explore if it really works as it reduces the hassle of changing water. I agree with Captk that this type of system is good for outdoor ponds as it requires some space to house the long tube and indoor tank may be difficult to install the system. Maybe there is some good DIY compact system available. I will try to build one if I have sufficient information on the concept and chemistry.

Ranchu: Here's the thread I was talking about.

Also, if you put a compact fluorescent light down over your sump, you could grow floating plants like duckweed, salvenia, frogbit or azolla down there.


2be: Yea... the things we do for our fish! LOL

Thank You Guys for all of your help and a special thanks to cptk . I will keep everyone posted and definately ask quuestions if anything goes wrong.

BTW: I forgot to mention why I even decided to test my ph level after so many months. My 6 in. common has a red streak on his tail. Has not gone away yet but (Zippy, his name) is acting normal and so is everyone else. I have 6 fish in this tank (55 gal.) and know eventually I will have to get another or bigger tank to seperate them. I have an emporer 400 and penguin 330 on the tank and a extra large bubble disk. All levels are good amonia 0, nitrate 10 , and nitrite 0 , ph 7.4 and kh between 143.2- 161.1ppm. The nitrate goes no higher than 20ppm within 7 days. Is there something I should be doing for Zippy?

Since he's acting fine, I'd just keep an eye on it.

Thanks DataGuru.
I will do just that. Will keep everyone posted.

wut up yall im new here, its a great forum
i got a problem

check it

i got two fish tanks rite
first one is about 30gallon with 7 Comet Goldfish are 3 inches
second is about 20gallon with 4 Comet Goldfish are 1.5-2 inches

the problem is the PH keeps crashin, like i cant keep it steady around 6.8-7.0

rite now it is below 6.0 its like 5.5

and i bought a PH increaser dat safely increases have been usin it fo 3 weeks but its all gone now

i do my regular water changes like every second or third day

anyone here know how to keep my PH rite...
is it good to add PH increaser all tha tyme?

how often should i do water changes?

Hi ThugLife,

Welcome to koko's!

I think you need to start a new thread with your problem. Few people will see this thread.

In the mean time, you need to get a GH & KH test kit. You need carbonate in the water to buffer pH swings. If you have little or no carbonate in the water (measured by KH/alkalinity) then you tank's pH can swing wildly and crash easily. An easy short term solution is to use of baking soda (bicarb of soda) to increase the KH. Longer term solution is along the line of crush shells or crushed corals in the tank.

However, I don't want to get into the dosage of BS until we can get some KH readings. We might be barking up the wrong tree afterall. Also test your source water KH as well.

BTW, you know that you are overstocking your tanks and that will only make the pH swing all the more likely.

What type of filters are you using? What are your ammonia and nitrIte readings?

Don't bother with commerical pH up/down type of product. They will bleed you dry. Fix it fundamentally, you will be fine.

thanks fo ya help

ya ill go out and buy a KH tester thangy


one question wut is KH?
i kno wut PH is...and for tha nitrates and ammonia they are fine the local petsmart said

KH is carbonate hardness or alkalinity. A measure of how much carbonate is in the water.