Recently my Fukien Tea bonsai has started losing strength and the leaves have started dropping off and drying up, so after researching online I believe it may be due to overwatering however I only water it when the soil is dry so I decided to check my water supply and have noticed some small worms swimming in the water. Could this be whats harming my bonsai?

Does anybody know how I can revive this bonsai so that I can re-pot it before summer starts?

I am going to re-pot this bonsai with an all-purpose mix: bonsai mix linkhttps://www.amazon.co.uk/Bonsai-Focus-Repotting-Mix-Litre/dp/B00BBAMIDK/ref=sr_1_3?adgrpid=50749475942&gclid=CjwKCAjw8e7mBRBsEiwAPVxxiD_9J-HnauN20iUYiUVLoLv9DR5tHBno3ILYn5b8xtDvfeaBnRO2lRoCY2cQAvD_BwE&hvadid=259098316026&hvdev=c&hvlocphy=9046300&hvnetw=g&hvpos=1t1&hvqmt=e&hvrand=13223129259181785914&hvtargid=kwd-366636040557&hydadcr=5977_1827735&keywords=bonsai+mix&qid=1557922178&s=gateway&sr=8-3